Re: xsrc/50386 (xterm on m68k broken due to libX11)

The cause of the problem is that libX11 poisons namespace of libc, by
shading the original stubs for thread operations by broken ones with
inappropriate prototype. You can find more details in an outstanding
analysis given by mlelstv@:

  http://mail-index.netbsd.org/port-m68k/2015/11/09/msg000647.html

The broken stubs are provided in
xsrc/external/mit/libX11/dist/src/UIThrStubs.c. As we already have our
own stubs in libc below src/lib/libc/thread-stub, I think we no longer
need them in libX11.

Looking into autoconf stuffs of libX11, UIThrStubs.c is intended to be
compiled if stub for pthread_self(3) is missing in libc. Actually, we
don't have it in libc; UIThrStubs.c provides stubs for more thread
operations than our libc does. However, if we need them, they should be
provided by libc, not libX11.

The attached patch below simply removes UIThrStubs.c from libX11. xterm
gets sanity with this patch on x68k. I also checked X server and few X
clients work fine with this patch on x68k, evbearmv7hfeb, and amd64.
However, I've not confirmed whether most other 3rd-party applications
work or not.

--- src/external/mit/xorg/lib/libX11/Makefile.libx11.orig	2015-11-09 19:43:39.000000000 +0900
+++ src/external/mit/xorg/lib/libX11/Makefile.libx11	2015-11-09 19:47:04.000000000 +0900
@@ -265,8 +265,8 @@
 	XlibInt.c \
 	Xrm.c
 
-SRCS+=	\
-	UIThrStubs.c 
+#SRCS+=	\
+#	UIThrStubs.c 
 
 SRCS+=	\
 	AddDIC.c \