Better handling of booleans in CMakeLists.txt
Updated the value of the version of cmake needed to build
ceres. Since the way booleans and literals are handled has changed
recently.

Change-Id: If13877f4403705cc29c3cf66c4e66dec26bbb3e9
diff --git a/internal/ceres/CMakeLists.txt b/internal/ceres/CMakeLists.txt
index 1b8b0d0..4cdf055 100644
--- a/internal/ceres/CMakeLists.txt
+++ b/internal/ceres/CMakeLists.txt
@@ -84,20 +84,20 @@
     visibility.cc
 )
 
-If (PROTOBUF_FOUND)
+If (${PROTOBUF_FOUND})
   PROTOBUF_GENERATE_CPP(PROTO_SRCS PROTO_HDRS matrix.proto)
-ENDIF (PROTOBUF_FOUND)
+ENDIF (${PROTOBUF_FOUND})
 
 # Also depend on the header files so that they appear in IDEs.
 FILE(GLOB CERES_INTERNAL_HDRS *.h)
 
 # Include the specialized schur solvers.
-IF (SCHUR_SPECIALIZATIONS)
+IF (${SCHUR_SPECIALIZATIONS})
   FILE(GLOB CERES_INTERNAL_SCHUR_FILES generated/*.cc)
-ELSE (SCHUR_SPECIALIZATIONS)
+ELSE (${SCHUR_SPECIALIZATIONS})
   # Only the fully dynamic solver.
   FILE(GLOB CERES_INTERNAL_SCHUR_FILES generated/schur_eliminator_d_d_d.cc)
-ENDIF (SCHUR_SPECIALIZATIONS)
+ENDIF (${SCHUR_SPECIALIZATIONS})
 
 ADD_LIBRARY(ceres
             ${PROTO_SRCS}
@@ -108,11 +108,11 @@
 
 SET(CERES_LIBRARY_DEPENDENCIES ${GLOG_LIB})
 
-IF (GFLAGS)
+IF (${GFLAGS})
   LIST(APPEND CERES_LIBRARY_DEPENDENCIES ${GFLAGS_LIB})
-ENDIF (GFLAGS)
+ENDIF (${GFLAGS})
 
-IF (SUITESPARSE)
+IF (${SUITESPARSE_FOUND})
   LIST(APPEND CERES_LIBRARY_DEPENDENCIES ${CHOLMOD_LIB})
   LIST(APPEND CERES_LIBRARY_DEPENDENCIES ${CCOLAMD_LIB})
   LIST(APPEND CERES_LIBRARY_DEPENDENCIES ${CAMD_LIB})
@@ -128,23 +128,23 @@
   IF (EXISTS ${BLAS_LIB})
     LIST(APPEND CERES_LIBRARY_DEPENDENCIES ${BLAS_LIB})
   ENDIF (EXISTS ${BLAS_LIB})
-ENDIF (SUITESPARSE)
+ENDIF (${SUITESPARSE_FOUND})
 
-IF (CXSPARSE)
+IF (${CXSPARSE_FOUND})
   LIST(APPEND CERES_LIBRARY_DEPENDENCIES ${CXSPARSE_LIB})
-ENDIF (CXSPARSE)
+ENDIF (${CXSPARSE_FOUND})
 
-IF (OPENMP_FOUND)
+IF (${OPENMP_FOUND})
   LIST(APPEND CERES_LIBRARY_DEPENDENCIES gomp)
-ENDIF (OPENMP_FOUND)
+ENDIF (${OPENMP_FOUND})
 
-IF (PROTOBUF_FOUND)
+IF (${PROTOBUF_FOUND})
   LIST(APPEND CERES_LIBRARY_DEPENDENCIES ${PROTOBUF_LIBRARY})
-ENDIF (PROTOBUF_FOUND)
+ENDIF (${PROTOBUF_FOUND})
 
 TARGET_LINK_LIBRARIES(ceres ${CERES_LIBRARY_DEPENDENCIES})
 
-IF (BUILD_TESTING)
+IF (${BUILD_TESTING})
   ADD_LIBRARY(gtest gmock_gtest_all.cc gmock_main.cc)
   ADD_LIBRARY(test_util test_util.cc)
   TARGET_LINK_LIBRARIES(gtest ${GFLAGS_LIB} ${GLOG_LIB})
@@ -203,7 +203,7 @@
   ENDIF (GFLAGS)
 
   # Large end to end test for the entire solver.
-  IF (GFLAGS)
+  IF (${GFLAGS})
     CERES_TEST(system)
-  ENDIF (GFLAGS)
-ENDIF (BUILD_TESTING)
+  ENDIF (${GFLAGS})
+ENDIF (${BUILD_TESTING})