Added patch for SDL

* The BOINC v6 screensaver expects the graphics app to bear a specific window class name
* It exits if the graphics app can't be found by that name!
* Ergo: patch SDL's default class name to trick (satisfy) BOINC :-)

build.sh

@@ -306,6 +306,10 @@ prepare_win32_environment()
 
 build_generic_win32()
 {
+	echo "Patching SDL..." | tee -a $LOGFILE
+	cd $ROOT/3rdparty/sdl/src/video/wincommon || failure
+	# patch: amend window class name (required by BOINC v6 screensaver!)
+	patch < $ROOT/patches/SDL_sysevents.c.patch >> $LOGFILE 2>&1 || failure
 	echo "Building SDL (this may take a while)..." | tee -a $LOGFILE
 	cd $ROOT/3rdparty/sdl || failure
 	chmod +x autogen.sh >> $LOGFILE 2>&1 || failure

patches/SDL_sysevents.c.patch

+--- SDL_sysevents.c	2009-04-17 17:18:07.000000000 +0200
++++ SDL_sysevents.c.new	2009-04-17 17:14:41.000000000 +0200
+@@ -799,7 +799,7 @@
+ #define CS_BYTEALIGNCLIENT	0
+ #endif
+ 	if ( ! name && ! SDL_Appname ) {
+-		name = "SDL_app";
++		name = "BOINC_app";
+ 		SDL_Appstyle = CS_BYTEALIGNCLIENT;
+ 		SDL_Instance = hInst ? hInst : SDL_GetModuleHandle();
+ 	}