Replace C types by stdint.h types

Not all occurrences have been replaced, in some cases they have been
left as they were before (like in rgbgfx and when they are in the
interface of a C standard library function).

Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>

include/link/library.h

@@ -1,6 +1,6 @@
 #ifndef RGBDS_LINK_LIBRARY_H
 #define RGBDS_LINK_LIBRARY_H
 
-extern void AddNeededModules(void);
+void AddNeededModules(void);
 
 #endif