Fixed bug 3476 - round() needs _GNU_SOURCE on some old systems Ozkan Sezer On systems with old glibc, such mine with glibc-2.8, the following warning is issued and is fixed easily by defining _GNU_SOURCE: /home/me/SDL2-2.0.5/src/video/x11/SDL_x11modes.c: In function 'CalculateXRandRRefreshRate': /home/me/SDL2-2.0.5/src/video/x11/SDL_x11modes.c:263: warning: implicit declaration of function 'round' /home/me/SDL2-2.0.5/src/video/x11/SDL_x11modes.c:263: warning: incompatible implicit declaration of built-in function 'round'
diff --git a/src/video/x11/SDL_x11modes.c b/src/video/x11/SDL_x11modes.c
index 29307b3..b1e3ff4 100644
--- a/src/video/x11/SDL_x11modes.c
+++ b/src/video/x11/SDL_x11modes.c
@@ -18,6 +18,10 @@
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
#include "../../SDL_internal.h"
#if SDL_VIDEO_DRIVER_X11