git-compat-util.h: add missing semicolon after struct itimerval

This hasn't been a problem in practice as almost all systems have the
setitimer() API (or it is provided by git in the case of mingw). This code
wasn't used in any default circumstances, as the build system never sets
NO_STRUCT_ITIMERVAL - this breakage only occured if the user asked for it.

We repair this case so we can rely on it in the following commits.

Signed-off-by: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-compat-util.h

@@ -191,7 +191,7 @@ extern int compat_mkdir_wo_trailing_slash(const char*, mode_t);
 struct itimerval {
 	struct timeval it_interval;
 	struct timeval it_value;
-}
+};
 #endif
 
 #ifdef NO_SETITIMER