On my system, building of all released versions of gnome-shell and the latest git revision fail for no reason other than the presence of the -Werror flag in the Makefiles. I know this because of the following text in the make output:

[...]
  CC     libgnome_shell_la-shell-wm.lo
  CC     libgnome_shell_la-shell-xfixes-cursor.lo
  CC     libgnome_shell_la-shell-recorder.lo
cc1: warnings being treated as errors
shell-window-tracker.c: In function 'get_app_for_window':
shell-window-tracker.c:396: error: implicit declaration of function 'meta_window_is_remote'
make[3]: *** [libgnome_shell_la-shell-window-tracker.lo] Error 1
make[3]: *** Waiting for unfinished jobs....
make[3]: Leaving directory `/home/user/gnome-shell/src'
make[2]: *** [all] Error 2
make[2]: Leaving directory `/home/user/gnome-shell/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/user/gnome-shell'
make: *** [all] Error 2

The workaround I've come up with is to use the following command to remove all of the -Werror flags from the Makefiles. After changing to the gnome-shell directory and running ./configure:

find . -name "Makefile" -exec grep -l \\-Werror '{}' \; | for file in $( cat - ); do cat $file | sed 's/-Werror//g' > $file.tmp; mv -f $file.tmp $file; done

After running that command, the build completes successfully. Even though this fixes the build, I would like to see the -Werror flag formally removed from the Makefile generator.

Relevant System Info:
Gentoo Linux ~amd64
gcc --version: gcc (Gentoo 4.4.3 p1.0) 4.4.3