split gralloc_priv.h and make sure it is C friendly
diff --git a/modules/gralloc/framebuffer.cpp b/modules/gralloc/framebuffer.cpp
index 5f97032..7d2b582 100644
--- a/modules/gralloc/framebuffer.cpp
+++ b/modules/gralloc/framebuffer.cpp
@@ -38,6 +38,7 @@
 #endif
 
 #include "gralloc_priv.h"
+#include "gr.h"
 
 /*****************************************************************************/