diff --git a/x11/9box/Makefile b/x11/9box/Makefile
index a1b863ee2d52..e8cc706044e1 100644
--- a/x11/9box/Makefile
+++ b/x11/9box/Makefile
@@ -16,6 +16,9 @@ USE_XORG=	xbitmaps x11 xt
 
 BUILD_WRKSRC=	${WRKSRC}/src
 
+# Dead upstream. Don't expect a proper fix.
+CFLAGS+=	-fcommon
+
 post-patch:
 	@${REINPLACE_CMD} -e 's|%%LOCALBASE%%|${LOCALBASE}|g; \
 		s|%%CC%%|${CC}|g' \