build-sys: use the appropriate autoconf macros for cflags

Don't bust CFLAGS passed on make command line please.

[airlied: wrap config.h include]
Signed-off-by: Marc-André Lureau <marcandre.lureau@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

configure.ac

@@ -11,6 +11,9 @@ AC_CONFIG_MACRO_DIR([build-aux])
 
 AM_INIT_AUTOMAKE([foreign dist-bzip2])
 
+AC_USE_SYSTEM_EXTENSIONS
+AC_PROG_CC_C99
+
 # Support silent build rules, requires at least automake-1.11. Disable
 # by either passing --disable-silent-rules to configure or passing V=1
 # to make
@@ -25,8 +28,6 @@ AC_SYS_LARGEFILE
 AC_CHECK_PROGS([PYTHON2], [python2 python])
 AX_CODE_COVERAGE
 
-DEFINES="-D_GNU_SOURCE"
-
 AC_ARG_ENABLE([debug],
     [AS_HELP_STRING([--enable-debug],
         [use debug compiler flags and macros @<:@default=disabled@:>@])],
@@ -79,11 +80,6 @@ XORG_DEFAULT_OPTIONS
 
 LIBDRM_REQUIRED=2.4.50
 
-dnl Add flags for gcc
-if test "x$GCC" = xyes; then
-	CFLAGS="$CFLAGS -Wall -std=c99"
-fi
-
 PKG_CHECK_MODULES([LIBDRM], [libdrm >= $LIBDRM_REQUIRED])
 PKG_CHECK_MODULES([EPOXY], [epoxy])
 

src/virgl_egl_context.c

@@ -26,6 +26,10 @@
 
 /* if we are using EGL and rendernodes then we talk via file descriptors to the remote
    node */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #define EGL_EGLEXT_PROTOTYPES
 #include <dirent.h>
 #include <fcntl.h>