Require glproto >= 1.4.8 for GLX.

It builds against 1.4.7 as well, but it hardcodes the GLX_EXT_tfp tokens that
were finalized in 1.4.8, so GLX_EXT_tfp breaks if the client side was built
against an older glproto. This will hopefully alert people to rebuild other
components (in particular Mesa) against the new glproto as well.
(cherry picked from 359d205 commit)

configure.ac

@@ -577,7 +577,7 @@ fi
 
 if test "x$GLX" = xyes && ! test "x$MESA_SOURCE" = x; then
 	PKG_CHECK_MODULES([XLIB], [x11])
-	PKG_CHECK_MODULES([GL], [glproto >= 1.4.7])
+	PKG_CHECK_MODULES([GL], [glproto >= 1.4.8])
 	AC_SUBST(XLIB_CFLAGS)
 	AC_DEFINE(GLXEXT, 1, [Build GLX extension])
 	GLX_LIBS='$(top_builddir)/GL/glx/libglx.la $(top_builddir)/GL/mesa/libGLcore.la'