Add missing arguments to boot_SDL(); this fixes a crash or failure in
Perl_xs_handshake() on some arches.  This patch does pass the CV of
the wrong function, but the handshake accepts it.

Index: src/SDL.xs
--- src/SDL.xs.orig
+++ src/SDL.xs
@@ -219,13 +219,13 @@ sdl_perl_atexit (void)
 	SDL_Quit();
 }
 
-void boot_SDL();
+void boot_SDL(pTHX_ CV *);
 void boot_SDL__OpenGL();
 
 XS(boot_SDL_perl)
 {
 	GET_TLS_CONTEXT
-	boot_SDL();
+	boot_SDL(aTHX_ cv);
 }
 
 MODULE = SDL_perl	PACKAGE = SDL
