If one compiles a Gtk+ program with -Wstrict-prototypes enabled, one will encounter this message:

/usr/include/gtk-2.0/gtk/gtkitemfactory.h:47: warning: function declaration isn’t a prototype [-Wstrict-prototypes]

This is quite annoying. An easy fix would be to use 

#pragma GCC diagnostic ignored "-Wno-strict-prototypes"

at the top of the header files, which disables strict prototype checking. That #pragma is new in some GCC 4.x version, so it might make sense to protect this:

#if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)
#pragma GCC diagnostic ignored "-Wno-strict-prototypes"
#endif

Of course, using this will disable the warning for the entire .c file. However, I'd argue that this shouldn't be much of a problem, since the -Wstrict-prototypes output is useless anyway here. Also, the user could still manually reenable that flag.

http://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html

Haven't prepped a patch for this yet. Can do if requested.