multimedia/aegisub: mark BROKEN

In file included from /wrkdirs/usr/ports/multimedia/aegisub/work/aegisub-3.2.2/libaegisub/include/libaegisub/mru.h:16:
In file included from /usr/local/include/boost/filesystem/path.hpp:21:
/usr/local/include/boost/filesystem/detail/path_traits.hpp:495:16: error: call to '_check_convertible_to_path_source' is ambiguous
        sizeof(is_convertible_to_path_source< T >::_check_convertible_to_path_source(boost::declval< T const& >())) == sizeof(yes_type);

Reported by:	pkg-fallout

multimedia/aegisub/Makefile

@@ -14,6 +14,7 @@ WWW=		http://www.aegisub.org/
 LICENSE=	BSD3CLAUSE
 LICENSE_FILE=	${WRKSRC}/LICENCE
 
+BROKEN=		fails to build
 BROKEN_aarch64=		Fails to compile: no support for this architecture (yet)
 NOT_FOR_ARCHS=		powerpc64 powerpc64le
 NOT_FOR_ARCHS_REASON_powerpc64=		No support for PowerPC 64 bit mode