Compatible with including as <SDL2/SDL.h>

sdl2.pc.in

@@ -11,4 +11,4 @@ Version: @SDL_VERSION@
 Requires:
 Conflicts:
 Libs: -L${libdir} @SDL_RLD_FLAGS@ @SDL_LIBS@ @PKGCONFIG_LIBS_PRIV@ @SDL_STATIC_LIBS@
-Cflags: -I${includedir}/SDL2 @SDL_CFLAGS@
+Cflags: -I${includedir} -I${includedir}/SDL2 @SDL_CFLAGS@