[sparc65] Fix build of net/gupnp/core

This fixes the build of net/gupnp/core for sparc64.

ok?

--Kurt

Index: Makefile
===================================================================
RCS file: /cvs/ports/net/gupnp/core/Makefile,v
retrieving revision 1.61
diff -u -p -r1.61 Makefile
--- Makefile 6 Jun 2021 08:16:19 -0000 1.61
+++ Makefile 11 Aug 2021 15:39:25 -0000
@@ -7,6 +7,9 @@ GNOME_VERSION= 1.2.7

SHARED_LIBS += gupnp-1.2 0.1

+COMPILER = base-clang ports-gcc
+COMPILER_LANGS = c
+
WANTLIB += gio-2.0 glib-2.0 gmodule-2.0 gobject-2.0 gssdp-1.2
WANTLIB += soup-2.4 xml2