Build without PIB support by default and add flag to enable it

include/SDL_config.h.cmake

@@ -473,6 +473,8 @@
 #cmakedefine SDL_IPHONE_KEYBOARD @SDL_IPHONE_KEYBOARD@
 #cmakedefine SDL_IPHONE_LAUNCHSCREEN @SDL_IPHONE_LAUNCHSCREEN@
 
+#cmakedefine SDL_VIDEO_VITA_PIB @SDL_VIDEO_VITA_PIB@
+
 #if !defined(__WIN32__) && !defined(__WINRT__)
 #  if !defined(_STDINT_H_) && !defined(_STDINT_H) && !defined(HAVE_STDINT_H) && !defined(_HAVE_STDINT_H)
 typedef unsigned int size_t;