Use GCC_FMT_ATTR (format checking)

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/qemu-error.h b/qemu-error.h
index 531ec63..4d5c537 100644
--- a/qemu-error.h
+++ b/qemu-error.h
@@ -30,7 +30,7 @@
 void loc_set_cmdline(char **argv, int idx, int cnt);
 void loc_set_file(const char *fname, int lno);
 
-void error_vprintf(const char *fmt, va_list ap);
+void error_vprintf(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
 void error_printf(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 void error_printf_unless_qmp(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 void error_print_loc(void);