[sparc64] Fix build of telephony/linphone/belle-sip

By default belle-sip is setting -Werror. We can turn it off by setting
ENABLE_STRICT=NO in CONFIGURE_ARGS.

This fixes the build on sparc64.

ok?

(cc maintainer)

--Kurt

Index: Makefile
===================================================================
RCS file: /cvs/ports/telephony/linphone/belle-sip/Makefile,v
retrieving revision 1.2
diff -u -p -r1.2 Makefile
--- Makefile 10 Jul 2021 16:58:01 -0000 1.2
+++ Makefile 9 Aug 2021 15:36:59 -0000
@@ -8,6 +8,7 @@ SHARED_LIBS += bellesip 0.0 # 1

CONFIGURE_ARGS= -DENABLE_STATIC=NO
CONFIGURE_ARGS += -DENABLE_TESTS=NO
+CONFIGURE_ARGS += -DENABLE_STRICT=NO

LIB_DEPENDS = telephony/linphone/bctoolbox \
telephony/linphone/belr