There are at least several reasons why base system X11 in netbsd-6 is
too old, resulting in pulling in parts of pkgsrc (modular) X11. This is
awkward and not super well debugged. One approach is to fix all the
bugs. Another is to switch netbsd-6 to pkgsrc X11, much like we
switched netbsd-5 long ago.
I don't particularly have a strong opinion - my netbsd-6 systems are
server-ish rather than desktop-ish. I'm bringing it up now because
right near the next freeze would be a bad time.
I haven't tested this at all, much less done a bulk build. It may be
that fixing the libX11/xcb bl3 issue fixes almost everything, and then
there's no real need.
--- NetBSD.mk.~1.49.~ 2017-02-04 20:39:57.000000000 -0500
+++ NetBSD.mk 2017-04-03 21:00:49.000000000 -0400
@@ -37,9 +37,9 @@ ULIMIT_CMD_memorysize?= ulimit -m `ulimi
ULIMIT_CMD_cputime?= ulimit -t `ulimit -H -t`
# Native X11 is only supported on NetBSD-5 and later.
-# On NetBSD-5, native X11 has enough issues that we default
+# On NetBSD-5 and -6, native X11 has enough issues that we default
# to modular.
-.if empty(MACHINE_PLATFORM:MNetBSD-[0-5].*)
+.if empty(MACHINE_PLATFORM:MNetBSD-[0-6].*)
X11_TYPE?= native
.endif