fix gflags windows linker warnings

CMakeLists.txt

@@ -583,10 +583,10 @@ endif (HAVE_PTHREAD)
 if (gflags_FOUND)
   target_link_libraries (glog PUBLIC gflags)
 
-  if (NOT BUILD_SHARED_LIBS)
-    # Don't use __declspec(dllexport|dllimport) if this is a static build
-    targeT_compile_definitions (glog PUBLIC GFLAGS_DLL_DECLARE_FLAG= GFLAGS_DLL_DEFINE_FLAG=)
-  endif (NOT BUILD_SHARED_LIBS)
+  target_compile_definitions (glog PRIVATE
+    GFLAGS_DLL_DECLARE_FLAG=GOOGLE_GLOG_DLL_DECL
+    GFLAGS_DLL_DEFINE_FLAG=GOOGLE_GLOG_DLL_DECL
+  )
 endif (gflags_FOUND)
 
 if (ANDROID)

src/glog/logging.h.in

@@ -86,6 +86,14 @@
 #include <inttypes.h>           // a third place for uint16_t or u_int16_t
 #endif
 
+#ifdef GFLAGS_DLL_DECLARE_FLAG
+#define GLOG_GFLAGS_DLL_DECLARE_FLAG_WAS_DEFINED
+#pragma push_macro("GFLAGS_DLL_DECLARE_FLAG")
+#undef GFLAGS_DLL_DECLARE_FLAG
+#endif // defined(GFLAGS_DLL_DECLARE_FLAG)
+
+#define GFLAGS_DLL_DECLARE_FLAG GOOGLE_GLOG_DLL_DECL
+
 #if @ac_cv_have_libgflags@
 #include <gflags/gflags.h>
 #endif
@@ -1876,4 +1884,9 @@ GOOGLE_GLOG_DLL_DECL void InstallFailureWriter(
 
 @ac_google_end_namespace@
 
+#ifdef GLOG_GFLAGS_DLL_DECLARE_FLAG_WAS_DEFINED
+#undef GLOG_GFLAGS_DLL_DECLARE_FLAG_WAS_DEFINED
+#pragma pop_macro("GFLAGS_DLL_DECLARE_FLAG")
+#endif // defined(GLOG_GFLAGS_DLL_DECLARE_FLAG_WAS_DEFINED)
+
 #endif // _LOGGING_H_

src/logging_custom_prefix_unittest.cc

@@ -29,7 +29,6 @@
 //
 // Author: Ray Sidney
 
-#include "config_for_unittests.h"
 #include "utilities.h"
 
 #include <fcntl.h>