This patch should make invesalius work again (#59269).

Note that if you run your apps with LIBGL_DIAGNOSTIC=1 mesa will act as if this
patch was not applied (making invesalius crash).

It reverts the following commit from mesa 7.8 branch:

From ad7d36e91933a49ce3f6ed2c14ae585a8a84fdf5 Mon Sep 17 00:00:00 2001
From: Aaron Plattner <aplattner@nvidia.com>
Date: Thu, 22 Apr 2010 16:30:42 +0000
Subject: Fix __glXInitializeVisualConfigFromTags's handling of unrecognized
fbconfig tags.

__glXInitializeVisualConfigFromTags doesn't skip the payload of
unrecognized tags.  Instead, it treats the value as if it were the
next tag, which can happen if the server's GLX extension is not
Mesa's.  For example, this falls down when NVIDIA sends a
GLX_FLOAT_COMPONENTS_NV = 0 pair, causing
__glXInitializeVisualConfigFromTags to bail out early.

Signed-off-by: Aaron Plattner <aplattner@nvidia.com>
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>

diff -p -up ./src/glx/glxext.c.orig ./src/glx/glxext.c
--- ./src/glx/glxext.c.orig	2010-10-02 00:51:28.000000000 +0200
+++ ./src/glx/glxext.c	2010-10-05 21:04:00.000000000 +0200
@@ -568,9 +568,6 @@ __glXInitializeVisualConfigFromTags(stru
              long int tagvalue = *bp++;
              fprintf(stderr, "WARNING: unknown GLX tag from server: "
                      "tag 0x%lx value 0x%lx\n", tag, tagvalue);
-         } else {
-             /* Ignore the unrecognized tag's value */
-             bp++;
          }
          break;
       }