sparc64 (and presumably other ld.bfd arches) need the addition of ${X11BASE}/lib to the LDFLAGS to build.
ok? (cc maintainer) --Kurt Index: Makefile =================================================================== RCS file: /cvs/ports/games/postal/Makefile,v retrieving revision 1.7 diff -u -p -r1.7 Makefile --- Makefile 12 Jul 2019 20:46:23 -0000 1.7 +++ Makefile 25 Apr 2020 21:55:05 -0000 @@ -25,7 +25,7 @@ LIB_DEPENDS = devel/sdl2 USE_GMAKE = Yes MAKE_FILE = makefile MAKE_FLAGS = CC="${CC}" CXX="${CXX}" LINKER="${CXX}" \ - LDFLAGS="${LDFLAGS} -L${LOCALBASE}/lib" + LDFLAGS="${LDFLAGS} -L${LOCALBASE}/lib -L${X11BASE}/lib" NO_TEST = Yes