Sparse fixes: NULL use, header order, ANSI prototypes, static

Fix Sparse warnings:
 * use NULL instead of plain 0
 * rearrange header include order to avoid redefining types accidentally
 * ANSIfy SLIRP
 * avoid "restrict" keyword
 * add static



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6736 c046a42c-6fe2-441c-8c8c-71466251a162

sdl.c

@@ -21,11 +21,6 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
-#include "qemu-common.h"
-#include "console.h"
-#include "sysemu.h"
-#include "x_keymap.h"
-
 #include <SDL.h>
 #include <SDL/SDL_syswm.h>
 
@@ -33,6 +28,11 @@
 #include <signal.h>
 #endif
 
+#include "qemu-common.h"
+#include "console.h"
+#include "sysemu.h"
+#include "x_keymap.h"
+
 static DisplayChangeListener *dcl;
 static SDL_Surface *real_screen;
 static SDL_Surface *guest_screen = NULL;