Add default Eigen install location on Windows to search paths.

Change-Id: If2e9999b04550269c94a86b8512d9dcc2842b91d

cmake/FindEigen.cmake

diff --git a/cmake/FindEigen.cmake b/cmake/FindEigen.cmake
index e245fb0..8e7609e 100644
--- a/cmake/FindEigen.cmake
+++ b/cmake/FindEigen.cmake
@@ -87,28 +87,22 @@
 #
 # TODO: Add standard Windows search locations for Eigen.
 LIST(APPEND EIGEN_CHECK_INCLUDE_DIRS
-  /usr/local/include/eigen3
-  /usr/local/homebrew/include/eigen3 # Mac OS X
-  /opt/local/var/macports/software/eigen3 # Mac OS X.
-  /opt/local/include/eigen3
-  /usr/include/eigen3)
+  /usr/local/include
+  /usr/local/homebrew/include # Mac OS X
+  /opt/local/var/macports/software # Mac OS X.
+  /opt/local/include
+  /usr/include)
+# Additional suffixes to try appending to each search path.
+LIST(APPEND EIGEN_CHECK_PATH_SUFFIXES
+  eigen3 # Default root directory for Eigen.
+  Eigen/include/eigen3 ) # Windows (for C:/Program Files prefix).
 
 # Search supplied hint directories first if supplied.
 FIND_PATH(EIGEN_INCLUDE_DIR
   NAMES Eigen/Core
   PATHS ${EIGEN_INCLUDE_DIR_HINTS}
-  ${EIGEN_CHECK_INCLUDE_DIRS})
-IF (NOT EIGEN_INCLUDE_DIR)
-  # Handle case where user / CMAKE_PREFIX_PATH does not specify the
-  # required eigen3 subdirectory, prepend it to search target and retry.
-  FIND_PATH(EIGEN_INCLUDE_DIR
-    NAMES eigen3/Eigen/Core
-    PATHS ${EIGEN_INCLUDE_DIR_HINTS}
-    ${EIGEN_CHECK_INCLUDE_DIRS})
-  IF (EIGEN_INCLUDE_DIR AND EXISTS ${EIGEN_INCLUDE_DIR})
-    UPDATE_CACHE_VARIABLE(EIGEN_INCLUDE_DIR "${EIGEN_INCLUDE_DIR}/eigen3")
-  ENDIF (EIGEN_INCLUDE_DIR AND EXISTS ${EIGEN_INCLUDE_DIR})
-ENDIF(NOT EIGEN_INCLUDE_DIR)
+  ${EIGEN_CHECK_INCLUDE_DIRS}
+  PATH_SUFFIXES ${EIGEN_CHECK_PATH_SUFFIXES})
 
 IF (NOT EIGEN_INCLUDE_DIR OR
     NOT EXISTS ${EIGEN_INCLUDE_DIR})