cmake/FindGflags.cmake - ceres-solver - Git at Google

 # Ceres Solver - A fast non-linear least squares minimizer
 # Copyright 2015 Google Inc. All rights reserved.
 # http://ceres-solver.org/
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are met:
 #
 # * Redistributions of source code must retain the above copyright notice,
 #   this list of conditions and the following disclaimer.
 # * Redistributions in binary form must reproduce the above copyright notice,
 #   this list of conditions and the following disclaimer in the documentation
 #   and/or other materials provided with the distribution.
 # * Neither the name of Google Inc. nor the names of its contributors may be
 #   used to endorse or promote products derived from this software without
 #   specific prior written permission.
 #
 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 #
 # Author: alexs.mac@gmail.com (Alex Stewart)
 #

 # FindGflags.cmake - Find Google gflags logging library.
 #
 # This module defines the following variables:
 #
 # GFLAGS_FOUND: TRUE iff gflags is found.
 # GFLAGS_INCLUDE_DIRS: Include directories for gflags.
 # GFLAGS_LIBRARIES: Libraries required to link gflags.
 # GFLAGS_NAMESPACE: The namespace in which gflags is defined.  In versions of
 #                   gflags < 2.1, this was google, for versions >= 2.1 it is
 #                   by default gflags, although can be configured when building
 #                   gflags to be something else (i.e. google for legacy
 #                   compatibility).
 #
 # The following variables control the behaviour of this module:
 #
 # GFLAGS_INCLUDE_DIR_HINTS: List of additional directories in which to
 #                           search for gflags includes, e.g: /timbuktu/include.
 # GFLAGS_LIBRARY_DIR_HINTS: List of additional directories in which to
 #                           search for gflags libraries, e.g: /timbuktu/lib.
 #
 # The following variables are also defined by this module, but in line with
 # CMake recommended FindPackage() module style should NOT be referenced directly
 # by callers (use the plural variables detailed above instead).  These variables
 # do however affect the behaviour of the module via FIND_[PATH/LIBRARY]() which
 # are NOT re-called (i.e. search for library is not repeated) if these variables
 # are set with valid values _in the CMake cache_. This means that if these
 # variables are set directly in the cache, either by the user in the CMake GUI,
 # or by the user passing -DVAR=VALUE directives to CMake when called (which
 # explicitly defines a cache variable), then they will be used verbatim,
 # bypassing the HINTS variables and other hard-coded search locations.
 #
 # GFLAGS_INCLUDE_DIR: Include directory for gflags, not including the
 #                     include directory of any dependencies.
 # GFLAGS_LIBRARY: gflags library, not including the libraries of any
 #                 dependencies.

 # Reset CALLERS_CMAKE_FIND_LIBRARY_PREFIXES to its value when
 # FindGflags was invoked.
 MACRO(GFLAGS_RESET_FIND_LIBRARY_PREFIX)
   IF (MSVC)
     SET(CMAKE_FIND_LIBRARY_PREFIXES "${CALLERS_CMAKE_FIND_LIBRARY_PREFIXES}")
   ENDIF (MSVC)
 ENDMACRO(GFLAGS_RESET_FIND_LIBRARY_PREFIX)

 # Called if we failed to find gflags or any of it's required dependencies,
 # unsets all public (designed to be used externally) variables and reports
 # error message at priority depending upon [REQUIRED/QUIET/<NONE>] argument.
 MACRO(GFLAGS_REPORT_NOT_FOUND REASON_MSG)
   UNSET(GFLAGS_FOUND)
   UNSET(GFLAGS_INCLUDE_DIRS)
   UNSET(GFLAGS_LIBRARIES)
   # Do not use unset, as we want to keep GFLAGS_NAMESPACE in the cache,
   # but simply clear its value.
   SET(GFLAGS_NAMESPACE "" CACHE STRING
     "gflags namespace (google or gflags)" FORCE)

   # Make results of search visible in the CMake GUI if gflags has not
   # been found so that user does not have to toggle to advanced view.
   MARK_AS_ADVANCED(CLEAR GFLAGS_INCLUDE_DIR
                          GFLAGS_LIBRARY
                          GFLAGS_NAMESPACE)

   GFLAGS_RESET_FIND_LIBRARY_PREFIX()

   # Note <package>_FIND_[REQUIRED/QUIETLY] variables defined by FindPackage()
   # use the camelcase library name, not uppercase.
   IF (Gflags_FIND_QUIETLY)
     MESSAGE(STATUS "Failed to find gflags - " ${REASON_MSG} ${ARGN})
   ELSEIF (Gflags_FIND_REQUIRED)
     MESSAGE(FATAL_ERROR "Failed to find gflags - " ${REASON_MSG} ${ARGN})
   ELSE()
     # Neither QUIETLY nor REQUIRED, use no priority which emits a message
     # but continues configuration and allows generation.
     MESSAGE("-- Failed to find gflags - " ${REASON_MSG} ${ARGN})
   ENDIF ()
 ENDMACRO(GFLAGS_REPORT_NOT_FOUND)

 # A cut down version of CMake's check_cxx_source_compiles() macro, which
 # supports specification of the CMAKE_BUILD_TYPE with which the test should
 # be compiled (but not REGEX matching of the output).  This is important
 # on Windows, for at least the NMake generator, which otherwise chooses
 # Debug, when the gflags library will typically be compiled in Release, and
 # MSVC will then fail to build, thus making all check_cxx_source_compiles()
 # tests fail.
 #
 # As per the CMake check_cxx_source_compiles() macro, we assume the following
 # variables can be set before this is invoked:
 #
 #    CMAKE_REQUIRED_FLAGS - String of compile command line flags.
 #    CMAKE_REQUIRED_DEFINITIONS - List of macros to define (-DFOO=bar).
 #    CMAKE_REQUIRED_INCLUDES - List of include directories.
 #    CMAKE_REQUIRED_LIBRARIES - List of libraries to link.
 #
 # This macro is a derivative of the CMake check_cxx_source_compiles() macro
 # distributed under the BSD License, Copyright 2005-2009 Kitware, Inc.
 MACRO(CHECK_CXX_SOURCE_COMPILES_WITH_BUILD_TYPE
     SOURCE BUILD_TYPE VAR)
   # Do not rerun test if output variable has an assigned value, ie is not
   # an empty string.
   IF ("${VAR}" MATCHES "^${VAR}$")
     # Verify that the BUILD_TYPE is sane.
     IF (NOT "${BUILD_TYPE}" STREQUAL "Release" AND
         NOT "${BUILD_TYPE}" STREQUAL "Debug" AND
         NOT "${BUILD_TYPE}" STREQUAL "RelWithDebInfo" AND
         NOT "${BUILD_TYPE}" STREQUAL "MinSizeRel" AND
         NOT "${BUILD_TYPE}" STREQUAL "")
       MESSAGE(FATAL_ERROR "Invalid BUILD_TYPE: ${BUILD_TYPE}, is not a "
         "valid CMAKE_BUILD_TYPE option.")
     ENDIF()

     SET(MACRO_CHECK_FUNCTION_DEFINITIONS
       "-D${VAR} ${CMAKE_REQUIRED_FLAGS}")

     SET(CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES)
     IF (CMAKE_REQUIRED_LIBRARIES)
       SET(CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES
         LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
     ENDIF()

     SET(CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES)
     IF (CMAKE_REQUIRED_INCLUDES)
       SET(CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES
         "-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
     ENDIF()

     FILE(WRITE "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/src.cxx"
       "${SOURCE}\n")

     MESSAGE(STATUS "Performing Test ${VAR}")
     # Pass the CMAKE_BUILD_TYPE to the CMake test project created to execute
     # the test (main difference over CMake's check_cxx_source_compiles() macro).
     TRY_COMPILE(${VAR}
       ${CMAKE_BINARY_DIR}
       ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/src.cxx
       COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
       ${CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES}
       CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_FUNCTION_DEFINITIONS}
       "-DCMAKE_BUILD_TYPE:STRING=${BUILD_TYPE}"
       "${CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES}"
       OUTPUT_VARIABLE OUTPUT)

     IF (${VAR})
       MESSAGE(STATUS "Performing Test ${VAR} - Success")
       SET(${VAR} 1 CACHE INTERNAL "Test ${VAR}")
       FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
         "Performing C++ SOURCE FILE Test ${VAR} succeded with the following output:\n"
         "${OUTPUT}\n"
         "Source file was:\n${SOURCE}\n")
     ELSE()
       MESSAGE(STATUS "Performing Test ${VAR} - Failed")
       SET(${VAR} "" CACHE INTERNAL "Test ${VAR}")
       FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
         "Performing C++ SOURCE FILE Test ${VAR} failed with the following output:\n"
         "${OUTPUT}\n"
         "Source file was:\n${SOURCE}\n")
     ENDIF()
   ENDIF()
 ENDMACRO()

 # Handle possible presence of lib prefix for libraries on MSVC, see
 # also GFLAGS_RESET_FIND_LIBRARY_PREFIX().
 IF (MSVC)
   # Preserve the caller's original values for CMAKE_FIND_LIBRARY_PREFIXES
   # s/t we can set it back before returning.
   SET(CALLERS_CMAKE_FIND_LIBRARY_PREFIXES "${CMAKE_FIND_LIBRARY_PREFIXES}")
   # The empty string in this list is important, it represents the case when
   # the libraries have no prefix (shared libraries / DLLs).
   SET(CMAKE_FIND_LIBRARY_PREFIXES "lib" "" "${CMAKE_FIND_LIBRARY_PREFIXES}")
 ENDIF (MSVC)

 # Search user-installed locations first, so that we prefer user installs
 # to system installs where both exist.
 #
 # TODO: Add standard Windows search locations for gflags.
 LIST(APPEND GFLAGS_CHECK_INCLUDE_DIRS
   /usr/local/include
   /usr/local/homebrew/include # Mac OS X
   /opt/local/var/macports/software # Mac OS X.
   /opt/local/include
   /usr/include)
 LIST(APPEND GFLAGS_CHECK_LIBRARY_DIRS
   /usr/local/lib
   /usr/local/homebrew/lib # Mac OS X.
   /opt/local/lib
   /usr/lib)

 # Search supplied hint directories first if supplied.
 FIND_PATH(GFLAGS_INCLUDE_DIR
   NAMES gflags/gflags.h
   PATHS ${GFLAGS_INCLUDE_DIR_HINTS}
   ${GFLAGS_CHECK_INCLUDE_DIRS})
 IF (NOT GFLAGS_INCLUDE_DIR OR
     NOT EXISTS ${GFLAGS_INCLUDE_DIR})
   GFLAGS_REPORT_NOT_FOUND(
     "Could not find gflags include directory, set GFLAGS_INCLUDE_DIR "
     "to directory containing gflags/gflags.h")
 ENDIF (NOT GFLAGS_INCLUDE_DIR OR
        NOT EXISTS ${GFLAGS_INCLUDE_DIR})

 FIND_LIBRARY(GFLAGS_LIBRARY NAMES gflags
   PATHS ${GFLAGS_LIBRARY_DIR_HINTS}
   ${GFLAGS_CHECK_LIBRARY_DIRS})
 IF (NOT GFLAGS_LIBRARY OR
     NOT EXISTS ${GFLAGS_LIBRARY})
   GFLAGS_REPORT_NOT_FOUND(
     "Could not find gflags library, set GFLAGS_LIBRARY "
     "to full path to libgflags.")
 ENDIF (NOT GFLAGS_LIBRARY OR
        NOT EXISTS ${GFLAGS_LIBRARY})

 # gflags typically requires a threading library (which is OS dependent), note
 # that this defines the CMAKE_THREAD_LIBS_INIT variable.  If we are able to
 # detect threads, we assume that gflags requires it.
 FIND_PACKAGE(Threads QUIET)
 SET(GFLAGS_LINK_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
 # On Windows (including MinGW), the Shlwapi library is used by gflags if
 # available.
 IF (WIN32)
   INCLUDE(CheckIncludeFileCXX)
   CHECK_INCLUDE_FILE_CXX("shlwapi.h" HAVE_SHLWAPI)
   IF (HAVE_SHLWAPI)
     LIST(APPEND GFLAGS_LINK_LIBRARIES shlwapi.lib)
   ENDIF(HAVE_SHLWAPI)
 ENDIF (WIN32)

 # Mark internally as found, then verify. GFLAGS_REPORT_NOT_FOUND() unsets
 # if called.
 SET(GFLAGS_FOUND TRUE)

 # Identify what namespace gflags was built with.
 IF (GFLAGS_INCLUDE_DIR AND NOT GFLAGS_NAMESPACE)
   # To handle Windows peculiarities / CMake bugs on MSVC we try two approaches
   # to detect the gflags namespace:
   #
   # 1) Try to use a custom version of check_cxx_source_compiles():
   #    check_cxx_source_compiles_with_build_type(),
   #    to compile a trivial program with the two choices for the gflags
   #    namespace.
   #
   #    This works on all OSs except Windows.  On Windows, if using NMake
   #    generator the previous method also works, if using Visual Studio, it does
   #    not, because our explicit instruction regarding the CMAKE_BUILD_TYPE is
   #    ignored by msbuild.  This breaks detection because MSVC requires that the
   #    build type of the test project used by check_cxx_source_compiles() match
   #    that of gflags.  However, msbuild forces the test project to use Debug,
   #    but gflags will be built in Release.
   #
   # 2) [In the event 1) fails] Use regex on the gflags.h header file to try to
   #    determine the gflags namespace.  Whilst this is less robust than 1),
   #    it does avoid any interaction with msbuild.

   # On Windows, it is required that the build type of the test app match that
   # of gflags, as CMAKE_BUILD_TYPE may not be defined when this is called, we
   # try each in turn.
   LIST(APPEND TEST_BUILD_TYPES Release Debug)
   FOREACH(BUILD_TYPE ${TEST_BUILD_TYPES})
     STRING(TOUPPER "${BUILD_TYPE}" BUILD_TYPE_UPPERCASE)
     # Setup include path & link library for gflags for CHECK_CXX_SOURCE_COMPILES.
     SET(CMAKE_REQUIRED_INCLUDES ${GFLAGS_INCLUDE_DIR})
     SET(CMAKE_REQUIRED_LIBRARIES ${GFLAGS_LIBRARY} ${GFLAGS_LINK_LIBRARIES})
     # First try the (older) google namespace.  Note that the output variable
     # MUST be unique to the build type as otherwise the test is not repeated as
     # it is assumed to have already been performed.
     CHECK_CXX_SOURCE_COMPILES_WITH_BUILD_TYPE(
       "#include <gflags/gflags.h>
      int main(int argc, char * argv[]) {
        google::ParseCommandLineFlags(&argc, &argv, true);
        return 0;
      }"
      ${BUILD_TYPE}
      GFLAGS_IN_GOOGLE_NAMESPACE_${BUILD_TYPE_UPPERCASE})
    IF (GFLAGS_IN_GOOGLE_NAMESPACE_${BUILD_TYPE_UPPERCASE})
      SET(GFLAGS_NAMESPACE google)
      BREAK()
    ELSE (GFLAGS_IN_GOOGLE_NAMESPACE_${BUILD_TYPE_UPPERCASE})
      # Try (newer) gflags namespace instead.  Note that the output variable
      # MUST be unique to the build type as otherwise the test is not repeated as
      # it is assumed to have already been performed.
      SET(CMAKE_REQUIRED_INCLUDES ${GFLAGS_INCLUDE_DIR})
      SET(CMAKE_REQUIRED_LIBRARIES ${GFLAGS_LIBRARY} ${GFLAGS_LINK_LIBRARIES})
      CHECK_CXX_SOURCE_COMPILES_WITH_BUILD_TYPE(
        "#include <gflags/gflags.h>
        int main(int argc, char * argv[]) {
          gflags::ParseCommandLineFlags(&argc, &argv, true);
          return 0;
        }"
        ${BUILD_TYPE}
        GFLAGS_IN_GFLAGS_NAMESPACE_${BUILD_TYPE_UPPERCASE})
      IF (GFLAGS_IN_GFLAGS_NAMESPACE_${BUILD_TYPE_UPPERCASE})
        SET(GFLAGS_NAMESPACE gflags)
        BREAK()
      ENDIF (GFLAGS_IN_GFLAGS_NAMESPACE_${BUILD_TYPE_UPPERCASE})
    ENDIF (GFLAGS_IN_GOOGLE_NAMESPACE_${BUILD_TYPE_UPPERCASE})
  ENDFOREACH()

  IF (NOT GFLAGS_NAMESPACE)
    # Failed to determine gflags namespace using
    # check_cxx_source_compiles_with_build_type() method, try and obtain it
    # using regex on the gflags header instead.
    MESSAGE(STATUS "Failed to find gflags namespace using using "
      "check_cxx_source_compiles(), trying namespace regex instead, "
      "this is expected on Windows.")
    # Scan gflags.h to identify what namespace gflags was built with.
    SET(GFLAGS_HEADER_FILE ${GFLAGS_INCLUDE_DIR}/gflags/gflags.h)
    IF (NOT EXISTS ${GFLAGS_HEADER_FILE})
      GFLAGS_REPORT_NOT_FOUND(
        "Could not find file: ${GFLAGS_HEADER_FILE} "
        "containing namespace information in gflags install located at: "
        "${GFLAGS_INCLUDE_DIR}.")
    ELSE (NOT EXISTS ${GFLAGS_HEADER_FILE})
      FILE(READ ${GFLAGS_HEADER_FILE} GFLAGS_HEADER_FILE_CONTENTS)

      STRING(REGEX MATCH "namespace [A-Za-z]+"
        GFLAGS_NAMESPACE "${GFLAGS_HEADER_FILE_CONTENTS}")
      STRING(REGEX REPLACE "namespace ([A-Za-z]+)" "\\1"
        GFLAGS_NAMESPACE "${GFLAGS_NAMESPACE}")

      IF (NOT GFLAGS_NAMESPACE)
       GFLAGS_REPORT_NOT_FOUND(
         "Failed to extract gflags namespace from header file: "
         "${GFLAGS_HEADER_FILE}.")
      ENDIF (NOT GFLAGS_NAMESPACE)

      # Verify that the namespace is either google or gflags.  Strictly
      # speaking the users can specify something else when building gflags,
      # but doing so would cause so many compatibility issues, that they should
      # not have done, so any mismatch is almost certainly a regex failure.
      IF (NOT GFLAGS_NAMESPACE STREQUAL "google" AND
          NOT GFLAGS_NAMESPACE STREQUAL "gflags")
        GFLAGS_REPORT_NOT_FOUND(
          "Failed to extract valid gflags namespace from header file: "
          "${GFLAGS_HEADER_FILE}, result: ${GFLAGS_NAMESPACE} is not "
          "google or gflags.")
      ENDIF()
    ENDIF (NOT EXISTS ${GFLAGS_HEADER_FILE})
  ENDIF (NOT GFLAGS_NAMESPACE)

  IF (NOT GFLAGS_NAMESPACE)
    GFLAGS_REPORT_NOT_FOUND(
      "Failed to determine gflags namespace either by "
      "check_cxx_source_compiles(), or namespace regex.")
  ENDIF (NOT GFLAGS_NAMESPACE)
 ENDIF (GFLAGS_INCLUDE_DIR AND NOT GFLAGS_NAMESPACE)

 # Make the GFLAGS_NAMESPACE a cache variable s/t the user can view it, and could
 # overwrite it in the CMake GUI.
 SET(GFLAGS_NAMESPACE "${GFLAGS_NAMESPACE}" CACHE STRING
   "gflags namespace (google or gflags)" FORCE)

 # gflags does not seem to provide any record of the version in its
 # source tree, thus cannot extract version.

 # Catch case when caller has set GFLAGS_NAMESPACE in the cache / GUI
 # with an invalid value.
 IF (GFLAGS_NAMESPACE AND
     NOT GFLAGS_NAMESPACE STREQUAL "google" AND
     NOT GFLAGS_NAMESPACE STREQUAL "gflags")
   GFLAGS_REPORT_NOT_FOUND(
     "Caller defined GFLAGS_NAMESPACE:"
     " ${GFLAGS_NAMESPACE} is not valid, not google or gflags.")
 ENDIF ()
 # Catch case when caller has set GFLAGS_INCLUDE_DIR in the cache / GUI and
 # thus FIND_[PATH/LIBRARY] are not called, but specified locations are
 # invalid, otherwise we would report the library as found.
 IF (GFLAGS_INCLUDE_DIR AND
     NOT EXISTS ${GFLAGS_INCLUDE_DIR}/gflags/gflags.h)
   GFLAGS_REPORT_NOT_FOUND(
     "Caller defined GFLAGS_INCLUDE_DIR:"
     " ${GFLAGS_INCLUDE_DIR} does not contain gflags/gflags.h header.")
 ENDIF (GFLAGS_INCLUDE_DIR AND
        NOT EXISTS ${GFLAGS_INCLUDE_DIR}/gflags/gflags.h)
 # TODO: This regex for gflags library is pretty primitive, we use lowercase
 #       for comparison to handle Windows using CamelCase library names, could
 #       this check be better?
 STRING(TOLOWER "${GFLAGS_LIBRARY}" LOWERCASE_GFLAGS_LIBRARY)
 IF (GFLAGS_LIBRARY AND
     NOT "${LOWERCASE_GFLAGS_LIBRARY}" MATCHES ".*gflags[^/]*")
   GFLAGS_REPORT_NOT_FOUND(
     "Caller defined GFLAGS_LIBRARY: "
     "${GFLAGS_LIBRARY} does not match gflags.")
 ENDIF (GFLAGS_LIBRARY AND
        NOT "${LOWERCASE_GFLAGS_LIBRARY}" MATCHES ".*gflags[^/]*")

 # Set standard CMake FindPackage variables if found.
 IF (GFLAGS_FOUND)
   SET(GFLAGS_INCLUDE_DIRS ${GFLAGS_INCLUDE_DIR})
   SET(GFLAGS_LIBRARIES ${GFLAGS_LIBRARY} ${GFLAGS_LINK_LIBRARIES})
 ENDIF (GFLAGS_FOUND)

 GFLAGS_RESET_FIND_LIBRARY_PREFIX()

 # Handle REQUIRED / QUIET optional arguments.
 INCLUDE(FindPackageHandleStandardArgs)
 FIND_PACKAGE_HANDLE_STANDARD_ARGS(Gflags DEFAULT_MSG
   GFLAGS_INCLUDE_DIRS GFLAGS_LIBRARIES GFLAGS_NAMESPACE)

 # Only mark internal variables as advanced if we found gflags, otherwise
 # leave them visible in the standard GUI for the user to set manually.
 IF (GFLAGS_FOUND)
   MARK_AS_ADVANCED(FORCE GFLAGS_INCLUDE_DIR
                          GFLAGS_LIBRARY
                          GFLAGS_NAMESPACE)
 ENDIF (GFLAGS_FOUND)
	# Ceres Solver - A fast non-linear least squares minimizer
	# Copyright 2015 Google Inc. All rights reserved.
	# http://ceres-solver.org/
	#
	# Redistribution and use in source and binary forms, with or without
	# modification, are permitted provided that the following conditions are met:
	#
	# * Redistributions of source code must retain the above copyright notice,
	# this list of conditions and the following disclaimer.
	# * Redistributions in binary form must reproduce the above copyright notice,
	# this list of conditions and the following disclaimer in the documentation
	# and/or other materials provided with the distribution.
	# * Neither the name of Google Inc. nor the names of its contributors may be
	# used to endorse or promote products derived from this software without
	# specific prior written permission.
	#
	# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
	# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	# POSSIBILITY OF SUCH DAMAGE.
	#
	# Author: alexs.mac@gmail.com (Alex Stewart)
	#

	# FindGflags.cmake - Find Google gflags logging library.
	#
	# This module defines the following variables:
	#
	# GFLAGS_FOUND: TRUE iff gflags is found.
	# GFLAGS_INCLUDE_DIRS: Include directories for gflags.
	# GFLAGS_LIBRARIES: Libraries required to link gflags.
	# GFLAGS_NAMESPACE: The namespace in which gflags is defined. In versions of
	# gflags < 2.1, this was google, for versions >= 2.1 it is
	# by default gflags, although can be configured when building
	# gflags to be something else (i.e. google for legacy
	# compatibility).
	#
	# The following variables control the behaviour of this module:
	#
	# GFLAGS_INCLUDE_DIR_HINTS: List of additional directories in which to
	# search for gflags includes, e.g: /timbuktu/include.
	# GFLAGS_LIBRARY_DIR_HINTS: List of additional directories in which to
	# search for gflags libraries, e.g: /timbuktu/lib.
	#
	# The following variables are also defined by this module, but in line with
	# CMake recommended FindPackage() module style should NOT be referenced directly
	# by callers (use the plural variables detailed above instead). These variables
	# do however affect the behaviour of the module via FIND_[PATH/LIBRARY]() which
	# are NOT re-called (i.e. search for library is not repeated) if these variables
	# are set with valid values _in the CMake cache_. This means that if these
	# variables are set directly in the cache, either by the user in the CMake GUI,
	# or by the user passing -DVAR=VALUE directives to CMake when called (which
	# explicitly defines a cache variable), then they will be used verbatim,
	# bypassing the HINTS variables and other hard-coded search locations.
	#
	# GFLAGS_INCLUDE_DIR: Include directory for gflags, not including the
	# include directory of any dependencies.
	# GFLAGS_LIBRARY: gflags library, not including the libraries of any
	# dependencies.

	# Reset CALLERS_CMAKE_FIND_LIBRARY_PREFIXES to its value when
	# FindGflags was invoked.
	MACRO(GFLAGS_RESET_FIND_LIBRARY_PREFIX)
	IF (MSVC)
	SET(CMAKE_FIND_LIBRARY_PREFIXES "${CALLERS_CMAKE_FIND_LIBRARY_PREFIXES}")
	ENDIF (MSVC)
	ENDMACRO(GFLAGS_RESET_FIND_LIBRARY_PREFIX)

	# Called if we failed to find gflags or any of it's required dependencies,
	# unsets all public (designed to be used externally) variables and reports
	# error message at priority depending upon [REQUIRED/QUIET/<NONE>] argument.
	MACRO(GFLAGS_REPORT_NOT_FOUND REASON_MSG)
	UNSET(GFLAGS_FOUND)
	UNSET(GFLAGS_INCLUDE_DIRS)
	UNSET(GFLAGS_LIBRARIES)
	# Do not use unset, as we want to keep GFLAGS_NAMESPACE in the cache,
	# but simply clear its value.
	SET(GFLAGS_NAMESPACE "" CACHE STRING
	"gflags namespace (google or gflags)" FORCE)

	# Make results of search visible in the CMake GUI if gflags has not
	# been found so that user does not have to toggle to advanced view.
	MARK_AS_ADVANCED(CLEAR GFLAGS_INCLUDE_DIR
	GFLAGS_LIBRARY
	GFLAGS_NAMESPACE)

	GFLAGS_RESET_FIND_LIBRARY_PREFIX()

	# Note <package>_FIND_[REQUIRED/QUIETLY] variables defined by FindPackage()
	# use the camelcase library name, not uppercase.
	IF (Gflags_FIND_QUIETLY)
	MESSAGE(STATUS "Failed to find gflags - " ${REASON_MSG} ${ARGN})
	ELSEIF (Gflags_FIND_REQUIRED)
	MESSAGE(FATAL_ERROR "Failed to find gflags - " ${REASON_MSG} ${ARGN})
	ELSE()
	# Neither QUIETLY nor REQUIRED, use no priority which emits a message
	# but continues configuration and allows generation.
	MESSAGE("-- Failed to find gflags - " ${REASON_MSG} ${ARGN})
	ENDIF ()
	ENDMACRO(GFLAGS_REPORT_NOT_FOUND)

	# A cut down version of CMake's check_cxx_source_compiles() macro, which
	# supports specification of the CMAKE_BUILD_TYPE with which the test should
	# be compiled (but not REGEX matching of the output). This is important
	# on Windows, for at least the NMake generator, which otherwise chooses
	# Debug, when the gflags library will typically be compiled in Release, and
	# MSVC will then fail to build, thus making all check_cxx_source_compiles()
	# tests fail.
	#
	# As per the CMake check_cxx_source_compiles() macro, we assume the following
	# variables can be set before this is invoked:
	#
	# CMAKE_REQUIRED_FLAGS - String of compile command line flags.
	# CMAKE_REQUIRED_DEFINITIONS - List of macros to define (-DFOO=bar).
	# CMAKE_REQUIRED_INCLUDES - List of include directories.
	# CMAKE_REQUIRED_LIBRARIES - List of libraries to link.
	#
	# This macro is a derivative of the CMake check_cxx_source_compiles() macro
	# distributed under the BSD License, Copyright 2005-2009 Kitware, Inc.
	MACRO(CHECK_CXX_SOURCE_COMPILES_WITH_BUILD_TYPE
	SOURCE BUILD_TYPE VAR)
	# Do not rerun test if output variable has an assigned value, ie is not
	# an empty string.
	IF ("${VAR}" MATCHES "^${VAR}$")
	# Verify that the BUILD_TYPE is sane.
	IF (NOT "${BUILD_TYPE}" STREQUAL "Release" AND
	NOT "${BUILD_TYPE}" STREQUAL "Debug" AND
	NOT "${BUILD_TYPE}" STREQUAL "RelWithDebInfo" AND
	NOT "${BUILD_TYPE}" STREQUAL "MinSizeRel" AND
	NOT "${BUILD_TYPE}" STREQUAL "")
	MESSAGE(FATAL_ERROR "Invalid BUILD_TYPE: ${BUILD_TYPE}, is not a "
	"valid CMAKE_BUILD_TYPE option.")
	ENDIF()

	SET(MACRO_CHECK_FUNCTION_DEFINITIONS
	"-D${VAR} ${CMAKE_REQUIRED_FLAGS}")

	SET(CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES)
	IF (CMAKE_REQUIRED_LIBRARIES)
	SET(CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES
	LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
	ENDIF()

	SET(CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES)
	IF (CMAKE_REQUIRED_INCLUDES)
	SET(CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES
	"-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
	ENDIF()

	FILE(WRITE "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/src.cxx"
	"${SOURCE}\n")

	MESSAGE(STATUS "Performing Test ${VAR}")
	# Pass the CMAKE_BUILD_TYPE to the CMake test project created to execute
	# the test (main difference over CMake's check_cxx_source_compiles() macro).
	TRY_COMPILE(${VAR}
	${CMAKE_BINARY_DIR}
	${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/src.cxx
	COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
	${CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES}
	CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_FUNCTION_DEFINITIONS}
	"-DCMAKE_BUILD_TYPE:STRING=${BUILD_TYPE}"
	"${CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES}"
	OUTPUT_VARIABLE OUTPUT)

	IF (${VAR})
	MESSAGE(STATUS "Performing Test ${VAR} - Success")
	SET(${VAR} 1 CACHE INTERNAL "Test ${VAR}")
	FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
	"Performing C++ SOURCE FILE Test ${VAR} succeded with the following output:\n"
	"${OUTPUT}\n"
	"Source file was:\n${SOURCE}\n")
	ELSE()
	MESSAGE(STATUS "Performing Test ${VAR} - Failed")
	SET(${VAR} "" CACHE INTERNAL "Test ${VAR}")
	FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
	"Performing C++ SOURCE FILE Test ${VAR} failed with the following output:\n"
	"${OUTPUT}\n"
	"Source file was:\n${SOURCE}\n")
	ENDIF()
	ENDIF()
	ENDMACRO()

	# Handle possible presence of lib prefix for libraries on MSVC, see
	# also GFLAGS_RESET_FIND_LIBRARY_PREFIX().
	IF (MSVC)
	# Preserve the caller's original values for CMAKE_FIND_LIBRARY_PREFIXES
	# s/t we can set it back before returning.
	SET(CALLERS_CMAKE_FIND_LIBRARY_PREFIXES "${CMAKE_FIND_LIBRARY_PREFIXES}")
	# The empty string in this list is important, it represents the case when
	# the libraries have no prefix (shared libraries / DLLs).
	SET(CMAKE_FIND_LIBRARY_PREFIXES "lib" "" "${CMAKE_FIND_LIBRARY_PREFIXES}")
	ENDIF (MSVC)

	# Search user-installed locations first, so that we prefer user installs
	# to system installs where both exist.
	#
	# TODO: Add standard Windows search locations for gflags.
	LIST(APPEND GFLAGS_CHECK_INCLUDE_DIRS
	/usr/local/include
	/usr/local/homebrew/include # Mac OS X
	/opt/local/var/macports/software # Mac OS X.
	/opt/local/include
	/usr/include)
	LIST(APPEND GFLAGS_CHECK_LIBRARY_DIRS
	/usr/local/lib
	/usr/local/homebrew/lib # Mac OS X.
	/opt/local/lib
	/usr/lib)

	# Search supplied hint directories first if supplied.
	FIND_PATH(GFLAGS_INCLUDE_DIR
	NAMES gflags/gflags.h
	PATHS ${GFLAGS_INCLUDE_DIR_HINTS}
	${GFLAGS_CHECK_INCLUDE_DIRS})
	IF (NOT GFLAGS_INCLUDE_DIR OR
	NOT EXISTS ${GFLAGS_INCLUDE_DIR})
	GFLAGS_REPORT_NOT_FOUND(
	"Could not find gflags include directory, set GFLAGS_INCLUDE_DIR "
	"to directory containing gflags/gflags.h")
	ENDIF (NOT GFLAGS_INCLUDE_DIR OR
	NOT EXISTS ${GFLAGS_INCLUDE_DIR})

	FIND_LIBRARY(GFLAGS_LIBRARY NAMES gflags
	PATHS ${GFLAGS_LIBRARY_DIR_HINTS}
	${GFLAGS_CHECK_LIBRARY_DIRS})
	IF (NOT GFLAGS_LIBRARY OR
	NOT EXISTS ${GFLAGS_LIBRARY})
	GFLAGS_REPORT_NOT_FOUND(
	"Could not find gflags library, set GFLAGS_LIBRARY "
	"to full path to libgflags.")
	ENDIF (NOT GFLAGS_LIBRARY OR
	NOT EXISTS ${GFLAGS_LIBRARY})

	# gflags typically requires a threading library (which is OS dependent), note
	# that this defines the CMAKE_THREAD_LIBS_INIT variable. If we are able to
	# detect threads, we assume that gflags requires it.
	FIND_PACKAGE(Threads QUIET)
	SET(GFLAGS_LINK_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
	# On Windows (including MinGW), the Shlwapi library is used by gflags if
	# available.
	IF (WIN32)
	INCLUDE(CheckIncludeFileCXX)
	CHECK_INCLUDE_FILE_CXX("shlwapi.h" HAVE_SHLWAPI)
	IF (HAVE_SHLWAPI)
	LIST(APPEND GFLAGS_LINK_LIBRARIES shlwapi.lib)
	ENDIF(HAVE_SHLWAPI)
	ENDIF (WIN32)

	# Mark internally as found, then verify. GFLAGS_REPORT_NOT_FOUND() unsets
	# if called.
	SET(GFLAGS_FOUND TRUE)

	# Identify what namespace gflags was built with.
	IF (GFLAGS_INCLUDE_DIR AND NOT GFLAGS_NAMESPACE)
	# To handle Windows peculiarities / CMake bugs on MSVC we try two approaches
	# to detect the gflags namespace:
	#
	# 1) Try to use a custom version of check_cxx_source_compiles():
	# check_cxx_source_compiles_with_build_type(),
	# to compile a trivial program with the two choices for the gflags
	# namespace.
	#
	# This works on all OSs except Windows. On Windows, if using NMake
	# generator the previous method also works, if using Visual Studio, it does
	# not, because our explicit instruction regarding the CMAKE_BUILD_TYPE is
	# ignored by msbuild. This breaks detection because MSVC requires that the
	# build type of the test project used by check_cxx_source_compiles() match
	# that of gflags. However, msbuild forces the test project to use Debug,
	# but gflags will be built in Release.
	#
	# 2) [In the event 1) fails] Use regex on the gflags.h header file to try to
	# determine the gflags namespace. Whilst this is less robust than 1),
	# it does avoid any interaction with msbuild.

	# On Windows, it is required that the build type of the test app match that
	# of gflags, as CMAKE_BUILD_TYPE may not be defined when this is called, we
	# try each in turn.
	LIST(APPEND TEST_BUILD_TYPES Release Debug)
	FOREACH(BUILD_TYPE ${TEST_BUILD_TYPES})
	STRING(TOUPPER "${BUILD_TYPE}" BUILD_TYPE_UPPERCASE)
	# Setup include path & link library for gflags for CHECK_CXX_SOURCE_COMPILES.
	SET(CMAKE_REQUIRED_INCLUDES ${GFLAGS_INCLUDE_DIR})
	SET(CMAKE_REQUIRED_LIBRARIES ${GFLAGS_LIBRARY} ${GFLAGS_LINK_LIBRARIES})
	# First try the (older) google namespace. Note that the output variable
	# MUST be unique to the build type as otherwise the test is not repeated as
	# it is assumed to have already been performed.
	CHECK_CXX_SOURCE_COMPILES_WITH_BUILD_TYPE(
	"#include <gflags/gflags.h>
	int main(int argc, char * argv[]) {
	google::ParseCommandLineFlags(&argc, &argv, true);
	return 0;
	}"
	${BUILD_TYPE}
	GFLAGS_IN_GOOGLE_NAMESPACE_${BUILD_TYPE_UPPERCASE})
	IF (GFLAGS_IN_GOOGLE_NAMESPACE_${BUILD_TYPE_UPPERCASE})
	SET(GFLAGS_NAMESPACE google)
	BREAK()
	ELSE (GFLAGS_IN_GOOGLE_NAMESPACE_${BUILD_TYPE_UPPERCASE})
	# Try (newer) gflags namespace instead. Note that the output variable
	# MUST be unique to the build type as otherwise the test is not repeated as
	# it is assumed to have already been performed.
	SET(CMAKE_REQUIRED_INCLUDES ${GFLAGS_INCLUDE_DIR})
	SET(CMAKE_REQUIRED_LIBRARIES ${GFLAGS_LIBRARY} ${GFLAGS_LINK_LIBRARIES})
	CHECK_CXX_SOURCE_COMPILES_WITH_BUILD_TYPE(
	"#include <gflags/gflags.h>
	int main(int argc, char * argv[]) {
	gflags::ParseCommandLineFlags(&argc, &argv, true);
	return 0;
	}"
	${BUILD_TYPE}
	GFLAGS_IN_GFLAGS_NAMESPACE_${BUILD_TYPE_UPPERCASE})
	IF (GFLAGS_IN_GFLAGS_NAMESPACE_${BUILD_TYPE_UPPERCASE})
	SET(GFLAGS_NAMESPACE gflags)
	BREAK()
	ENDIF (GFLAGS_IN_GFLAGS_NAMESPACE_${BUILD_TYPE_UPPERCASE})
	ENDIF (GFLAGS_IN_GOOGLE_NAMESPACE_${BUILD_TYPE_UPPERCASE})
	ENDFOREACH()

	IF (NOT GFLAGS_NAMESPACE)
	# Failed to determine gflags namespace using
	# check_cxx_source_compiles_with_build_type() method, try and obtain it
	# using regex on the gflags header instead.
	MESSAGE(STATUS "Failed to find gflags namespace using using "
	"check_cxx_source_compiles(), trying namespace regex instead, "
	"this is expected on Windows.")
	# Scan gflags.h to identify what namespace gflags was built with.
	SET(GFLAGS_HEADER_FILE ${GFLAGS_INCLUDE_DIR}/gflags/gflags.h)
	IF (NOT EXISTS ${GFLAGS_HEADER_FILE})
	GFLAGS_REPORT_NOT_FOUND(
	"Could not find file: ${GFLAGS_HEADER_FILE} "
	"containing namespace information in gflags install located at: "
	"${GFLAGS_INCLUDE_DIR}.")
	ELSE (NOT EXISTS ${GFLAGS_HEADER_FILE})
	FILE(READ ${GFLAGS_HEADER_FILE} GFLAGS_HEADER_FILE_CONTENTS)

	STRING(REGEX MATCH "namespace [A-Za-z]+"
	GFLAGS_NAMESPACE "${GFLAGS_HEADER_FILE_CONTENTS}")
	STRING(REGEX REPLACE "namespace ([A-Za-z]+)" "\\1"
	GFLAGS_NAMESPACE "${GFLAGS_NAMESPACE}")

	IF (NOT GFLAGS_NAMESPACE)
	GFLAGS_REPORT_NOT_FOUND(
	"Failed to extract gflags namespace from header file: "
	"${GFLAGS_HEADER_FILE}.")
	ENDIF (NOT GFLAGS_NAMESPACE)

	# Verify that the namespace is either google or gflags. Strictly
	# speaking the users can specify something else when building gflags,
	# but doing so would cause so many compatibility issues, that they should
	# not have done, so any mismatch is almost certainly a regex failure.
	IF (NOT GFLAGS_NAMESPACE STREQUAL "google" AND
	NOT GFLAGS_NAMESPACE STREQUAL "gflags")
	GFLAGS_REPORT_NOT_FOUND(
	"Failed to extract valid gflags namespace from header file: "
	"${GFLAGS_HEADER_FILE}, result: ${GFLAGS_NAMESPACE} is not "
	"google or gflags.")
	ENDIF()
	ENDIF (NOT EXISTS ${GFLAGS_HEADER_FILE})
	ENDIF (NOT GFLAGS_NAMESPACE)

	IF (NOT GFLAGS_NAMESPACE)
	GFLAGS_REPORT_NOT_FOUND(
	"Failed to determine gflags namespace either by "
	"check_cxx_source_compiles(), or namespace regex.")
	ENDIF (NOT GFLAGS_NAMESPACE)
	ENDIF (GFLAGS_INCLUDE_DIR AND NOT GFLAGS_NAMESPACE)

	# Make the GFLAGS_NAMESPACE a cache variable s/t the user can view it, and could
	# overwrite it in the CMake GUI.
	SET(GFLAGS_NAMESPACE "${GFLAGS_NAMESPACE}" CACHE STRING
	"gflags namespace (google or gflags)" FORCE)

	# gflags does not seem to provide any record of the version in its
	# source tree, thus cannot extract version.

	# Catch case when caller has set GFLAGS_NAMESPACE in the cache / GUI
	# with an invalid value.
	IF (GFLAGS_NAMESPACE AND
	NOT GFLAGS_NAMESPACE STREQUAL "google" AND
	NOT GFLAGS_NAMESPACE STREQUAL "gflags")
	GFLAGS_REPORT_NOT_FOUND(
	"Caller defined GFLAGS_NAMESPACE:"
	" ${GFLAGS_NAMESPACE} is not valid, not google or gflags.")
	ENDIF ()
	# Catch case when caller has set GFLAGS_INCLUDE_DIR in the cache / GUI and
	# thus FIND_[PATH/LIBRARY] are not called, but specified locations are
	# invalid, otherwise we would report the library as found.
	IF (GFLAGS_INCLUDE_DIR AND
	NOT EXISTS ${GFLAGS_INCLUDE_DIR}/gflags/gflags.h)
	GFLAGS_REPORT_NOT_FOUND(
	"Caller defined GFLAGS_INCLUDE_DIR:"
	" ${GFLAGS_INCLUDE_DIR} does not contain gflags/gflags.h header.")
	ENDIF (GFLAGS_INCLUDE_DIR AND
	NOT EXISTS ${GFLAGS_INCLUDE_DIR}/gflags/gflags.h)
	# TODO: This regex for gflags library is pretty primitive, we use lowercase
	# for comparison to handle Windows using CamelCase library names, could
	# this check be better?
	STRING(TOLOWER "${GFLAGS_LIBRARY}" LOWERCASE_GFLAGS_LIBRARY)
	IF (GFLAGS_LIBRARY AND
	NOT "${LOWERCASE_GFLAGS_LIBRARY}" MATCHES ".gflags[^/]")
	GFLAGS_REPORT_NOT_FOUND(
	"Caller defined GFLAGS_LIBRARY: "
	"${GFLAGS_LIBRARY} does not match gflags.")
	ENDIF (GFLAGS_LIBRARY AND
	NOT "${LOWERCASE_GFLAGS_LIBRARY}" MATCHES ".gflags[^/]")

	# Set standard CMake FindPackage variables if found.
	IF (GFLAGS_FOUND)
	SET(GFLAGS_INCLUDE_DIRS ${GFLAGS_INCLUDE_DIR})
	SET(GFLAGS_LIBRARIES ${GFLAGS_LIBRARY} ${GFLAGS_LINK_LIBRARIES})
	ENDIF (GFLAGS_FOUND)

	GFLAGS_RESET_FIND_LIBRARY_PREFIX()

	# Handle REQUIRED / QUIET optional arguments.
	INCLUDE(FindPackageHandleStandardArgs)
	FIND_PACKAGE_HANDLE_STANDARD_ARGS(Gflags DEFAULT_MSG
	GFLAGS_INCLUDE_DIRS GFLAGS_LIBRARIES GFLAGS_NAMESPACE)

	# Only mark internal variables as advanced if we found gflags, otherwise
	# leave them visible in the standard GUI for the user to set manually.
	IF (GFLAGS_FOUND)
	MARK_AS_ADVANCED(FORCE GFLAGS_INCLUDE_DIR
	GFLAGS_LIBRARY
	GFLAGS_NAMESPACE)
	ENDIF (GFLAGS_FOUND)