SDL: Silence a large number of compile warnings (WIP)

There are some real bugs in here, but we're drowning in warnings.

Change-Id: I7c2c0eafc8426327521bdd8a3ac2d3742ac16864

apps/plugins/sdl/include/SDL_config_rockbox.h

@@ -92,6 +92,9 @@
 #undef strdup
 
 /* clock() wraps current_tick */
+#ifdef CLOCKS_PER_SEC
+#undef CLOCKS_PER_SEC
+#endif
 #define CLOCKS_PER_SEC HZ
 
 /*
@@ -160,9 +163,13 @@
 #define strlcpy rb->strlcpy
 #define strlen rb->strlen
 #define strncasecmp rb->strncasecmp
+#ifndef strncat
 #define strncat rb->strlcat /* hack */
+#endif
 #define strncmp rb->strncmp
+#ifndef strncat
 #define strpbrk strpbrk_wrapper
+#endif
 #define strrchr rb->strrchr
 #define strstr SDL_strstr
 #define strtok strtok_wrapper