st/glx/xlib: ship the SConscript in the release tarball

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Acked-by: Matt Turner <mattst88@gmail.com>

src/gallium/state_trackers/glx/xlib/Makefile.am

@@ -34,3 +34,5 @@ AM_CPPFLAGS = \
 noinst_LTLIBRARIES = libxlib.la
 
 libxlib_la_SOURCES = $(C_SOURCES)
+
+EXTRA_DIST = SConscript