Remove redefinition of _GNU_SOURCE and __USE_GNU

Now _GNU_SOURCE is already defined globally in configure.in.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

src/control/hcontrol.c

@@ -48,9 +48,6 @@ to reduce overhead accessing the real controls in kernel drivers.
 #include <string.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
-#ifndef DOC_HIDDEN
-#define __USE_GNU
-#endif
 #include "control_local.h"
 #ifdef HAVE_LIBPTHREAD
 #include <pthread.h>

src/dlmisc.c

@@ -27,7 +27,6 @@
  *
  */
 
-#define _GNU_SOURCE
 #include "list.h"
 #include "local.h"
 

src/timer/timer_hw.c

@@ -23,7 +23,6 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
-#define __USE_GNU
 #include <fcntl.h>
 #include <sys/ioctl.h>
 #include "timer_local.h"