SDL UI, fix SDL input and SDL window output mode for osx compile

NB for osx >= 10.14 you need SDL >= rev 13688 (ATM only available from SDL repo)

platform/common/main.c

@@ -10,6 +10,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <strings.h>
+#ifdef USE_SDL
+#include <SDL.h>
+#endif
 
 #include "../libpicofe/input.h"
 #include "../libpicofe/plat.h"
@@ -83,12 +86,12 @@ int main(int argc, char *argv[])
 
 	plat_target_init();
 	plat_init();
+	menu_init();
 
 	emu_prep_defconfig(); // depends on input
 	emu_read_config(NULL, 0);
 
 	emu_init();
-	menu_init();
 
 #ifdef GPERF
 	ProfilerStart("gperf.out");