Make GEClientGone static and include registry.h, to fix the following
warnings:
geext.c:225: warning: no previous prototype for 'GEClientGone'
geext.c: In function 'GEExtensionInit':
geext.c:280: warning: implicit declaration of function 'RegisterResourceName'
geext.c:280: warning: nested extern declaration of 'RegisterResourceName'