Remove _GNU_SOURCE flag from APPLE builds

_GNU_SOURCE should not have been defined in the first place for OSX, and
then it should have defaulted to using non-thread-specific locale. This
fixes future such problems.

In this case the Linux and apple interface to thread-specific locale
seems to be the same, why I keep the xlocale header instead of
defaulting to process-specific.

CMakeLists.txt

@@ -284,7 +284,7 @@ endif()
 if(FMILIB_BUILD_SHARED_LIB)
 	add_library(fmilib_shared SHARED ${FMILIB_SHARED_SRC})
 
-    if (UNIX)
+    if (UNIX AND NOT APPLE)
         target_compile_definitions(fmilib_shared PRIVATE -D_GNU_SOURCE)
     endif()
 

Config.cmake/jmutil.cmake

@@ -62,8 +62,11 @@ endif(CYGWIN)
 
 target_link_libraries(jmutils c99snprintf)
 
-if(UNIX)
+if(UNIX AND NOT APPLE)
     target_compile_definitions(jmutils PRIVATE -D_GNU_SOURCE)
+endif()
+
+if(UNIX)
 	target_link_libraries(jmutils dl)
 endif(UNIX)
 if(WIN32)

src/Util/src/JM/jm_portability.c

@@ -18,7 +18,13 @@
 #include <string.h>
 
 #include <locale.h>
+
+#if defined(_GNU_SOURCE) || defined(__APPLE__)
+#define UNIX_THREAD_LOCALE
+#endif
+
 #ifdef __APPLE__
+/* Include thread-specific locale functions for OSX. */
 #include <xlocale.h>
 #endif
 
@@ -361,7 +367,7 @@ int jm_snprintf(char * str, size_t size, const char * fmt, ...) {
 }
 
 struct jm_locale_t {
-#ifdef _GNU_SOURCE
+#ifdef UNIX_THREAD_LOCALE
     locale_t locale_old;
 #else
     char* locale_old;
@@ -379,7 +385,7 @@ jm_locale_t* jm_setlocale_numeric(jm_callbacks* cb, const char* value) {
 		return NULL;
 	}
 
-#ifdef _GNU_SOURCE
+#ifdef UNIX_THREAD_LOCALE
 	{
 		locale_t nloc = NULL;
 
@@ -450,7 +456,7 @@ int jm_resetlocale_numeric(jm_callbacks* cb, jm_locale_t* jmloc) {
 		return 1; /* impl. error */
 	}
 
-#ifdef _GNU_SOURCE
+#ifdef UNIX_THREAD_LOCALE
 	{
 		/* Get current locale, which is expected to have been set with a previous
 		 * call to 'jm_setlocale_numeric'. */