x11/gtk+3 uses C99 constructs, so we need to less base-gcc know that. ok?
--Kurt Index: Makefile =================================================================== RCS file: /cvs/ports/x11/gtk+3/Makefile,v retrieving revision 1.232 diff -u -r1.232 Makefile --- Makefile 30 Jun 2020 10:20:47 -0000 1.232 +++ Makefile 3 Jul 2020 06:35:02 -0000 @@ -116,6 +116,11 @@ CONFIGURE_ARGS += --disable-colord .endif +.include <bsd.port.arch.mk> +.if !${PROPERTIES:Mclang} +CFLAGS += -std=gnu99 +.endif + FAKE_FLAGS= sysconfdir=${PREFIX}/share/examples/gtk+3 # configure will disable lpr in default gtk-print-backends if cups is found