Make it compile with SDL2 again

For some reason SDL.h (or headers included by it) need some
string functions (like strncmp) in inline-functions (that we
don't even use).
Str.h has #defines preventing their usage.. so #undef those in
the (few) sourcefiles that need SDL headers

neo/sys/sdl/sdl_cpu.cpp

@@ -26,12 +26,19 @@ If you have questions concerning this license or the applicable additional terms
 
 ===========================================================================
 */
-#include <SDL_cpuinfo.h>
 
 #pragma hdrstop
 #include "../../idlib/precompiled.h"
 
-//#include "win_local.h"
+// DG: SDL_*.h somehow needs the following functions, so #undef those silly
+//     "don't use" #defines from Str.h
+#undef strcasecmp
+#undef strncmp
+#undef vsnprintf
+// DG end
+
+#include <SDL_cpuinfo.h>
+
 
 #pragma warning(disable:4740)	// warning C4740: flow in or out of inline asm code suppresses global optimization
 #pragma warning(disable:4731)	// warning C4731: 'XXX' : frame pointer register 'ebx' modified by inline assembly code

neo/sys/sdl/sdl_events.cpp

@@ -31,6 +31,13 @@ If you have questions concerning this license or the applicable additional terms
 
 #include "../../idlib/precompiled.h"
 
+// DG: SDL.h somehow needs the following functions, so #undef those silly
+//     "don't use" #defines from Str.h
+#undef strncmp
+#undef strcasecmp
+#undef vsnprintf
+// DG end
+
 #include <SDL.h>
 
 #include "renderer/tr_local.h"

neo/sys/sdl/sdl_glimp.cpp

@@ -29,11 +29,18 @@ If you have questions concerning this license or the applicable additional terms
 ===========================================================================
 */
 
+#include "../../idlib/precompiled.h"
+
+// DG: SDL.h somehow needs the following functions, so #undef those silly
+//     "don't use" #defines from Str.h
+#undef strncmp
+#undef strcasecmp
+#undef vsnprintf
+// DG end
+
 #include <SDL.h>
 #include <SDL_syswm.h>
 
-#include "../../idlib/precompiled.h"
-
 #include "renderer/tr_local.h"
 #include "sdl_local.h"