Add header files to add_library targets so they show up in IDEs.

CMakeLists.txt

@@ -133,8 +133,8 @@ include_directories ("${PROJECT_SOURCE_DIR}/src")
 include_directories ("${PROJECT_BINARY_DIR}/include")
 include_directories ("${PROJECT_BINARY_DIR}/include/${GFLAGS_NAMESPACE}")
 
-add_library (gflags           ${GFLAGS_SRCS})
-add_library (gflags_nothreads ${GFLAGS_SRCS})
+add_library (gflags           ${GFLAGS_SRCS} ${PRIVATE_HDRS} ${PUBLIC_HDRS})
+add_library (gflags_nothreads ${GFLAGS_SRCS} ${PRIVATE_HDRS} ${PUBLIC_HDRS})
 set_target_properties (gflags_nothreads PROPERTIES COMPILE_DEFINITIONS NO_THREADS)
 
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