This patch makes GTK+ look for additional modules in a list of directories
specified by the environment variable "GUIX_GTK2_PATH".  This can be used
instead of "GTK_PATH" to make GTK+ find modules that are incompatible with
other major versions of GTK+.

--- a/gtk/gtkmodules.c	2014-09-29 22:02:17.000000000 +0200
+++ b/gtk/gtkmodules.c	2015-12-02 18:41:53.306396938 +0100
@@ -55,6 +55,7 @@
 get_module_path (void)
 {
   const gchar *module_path_env;
+  const gchar *module_guix_gtk2_path_env;
   const gchar *exe_prefix;
   const gchar *home_dir;
   gchar *home_gtk_dir = NULL;
@@ -70,6 +71,7 @@
     home_gtk_dir = g_build_filename (home_dir, ".gtk-2.0", NULL);
 
   module_path_env = g_getenv ("GTK_PATH");
+  module_guix_gtk2_path_env = g_getenv ("GUIX_GTK2_PATH");
   exe_prefix = g_getenv ("GTK_EXE_PREFIX");
 
   if (exe_prefix)
@@ -77,9 +79,21 @@
   else
     default_dir = g_build_filename (GTK_LIBDIR, "gtk-2.0", NULL);
 
-  if (module_path_env && home_gtk_dir)
+  if (module_guix_gtk2_path_env && module_path_env && home_gtk_dir)
+    module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
+				module_guix_gtk2_path_env, module_path_env, home_gtk_dir, default_dir, NULL);
+  else if (module_guix_gtk2_path_env && home_gtk_dir)
+    module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
+				module_guix_gtk2_path_env, home_gtk_dir, default_dir, NULL);
+  else if (module_guix_gtk2_path_env && module_path_env)
+    module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
+				module_guix_gtk2_path_env, module_path_env, default_dir, NULL);
+  else if (module_path_env && home_gtk_dir)
     module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
 				module_path_env, home_gtk_dir, default_dir, NULL);
+  else if (module_guix_gtk2_path_env)
+    module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
+				module_guix_gtk2_path_env, default_dir, NULL);
   else if (module_path_env)
     module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
 				module_path_env, default_dir, NULL);
iv class='path'>path: <a href='/guix/log/?id=37d0befca0cd346046b094025dcc2051047f39d8'>root</a>/<a href='/guix/log/gnu?id=37d0befca0cd346046b094025dcc2051047f39d8'>gnu</a>/<a href='/guix/log/gnu/packages?id=37d0befca0cd346046b094025dcc2051047f39d8'>packages</a>/<a href='/guix/log/gnu/packages/tls.scm?id=37d0befca0cd346046b094025dcc2051047f39d8'>tls.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/tls.scm?id=37d0befca0cd346046b094025dcc2051047f39d8&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-09-28 11:44:08 +0200'>2023-09-28</span></td><td><a href='/guix/commit/gnu/packages/tls.scm?id=51e1df07b1d21840551eb8dc15b4bfe5612e1bf9'>gnu: openssl@1.1: Upgrade replacement to 1.1.1u.</a><span class='msg-avail'>...<span class='msg-tooltip'>Includes fixes for CVE-2023-0215, CVE-2023-0286, CVE-2023-0464, CVE-2023-0465,
CVE-2023-0466, CVE-2023-2650, CVE-2022-4304, CVE-2022-4450.

* gnu/packages/tls.scm (openssl/fixed): Update to 1.1.1u.

Co-authored-by: Denis 'GNUtoo' Carikli &lt;GNUtoo@cyberdimension.org&gt;
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-09-28 11:44:08 +0200'>2023-09-28</span></td><td><a href='/guix/commit/gnu/packages/tls.scm?id=e67cb380f78af1be21e550b42e88ee28e524d886'>gnu: openssl@1.1: Really replace with fixed version.</a><span class='msg-avail'>...<span class='msg-tooltip'>The ‘replacement’ field of ‘openssl-1.1’ was apparently lost in a
previous merge commit ca. Jan. 2023; consequently, ‘openssl/fixed’ was
unused.

* gnu/packages/tls.scm (openssl-1.1)[replacement]: New field.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-08-13 02:00:00 +0200'>2023-08-13</span></td><td><a href='/guix/commit/gnu/packages/tls.scm?id=310b0f72d8749376832fa1f149837a83d8e74629'>gnu: libressl: Update to 3.7.3 [fixes CVE-2023-35784].</a><span class='msg-avail'>...<span class='msg-tooltip'>Thanks to Dennis 'GNUtoo' Carikli for &lt;https://issues.guix.gnu.org/64982&gt;,
but upgrading to 3.8.0 breaks (at least) OpenSMTPd.

* gnu/packages/tls.scm (libressl): Update to 3.7.3.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2023-07-20 10:11:35 +0200'>2023-07-20</span></td><td><a href='/guix/commit/gnu/packages/tls.scm?id=fb6f94864d1c1b3a6c46f3b880b8a51003854f89'>gnu: openssl-1.1: Fix shared build for the Hurd.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/tls.scm (openssl-1.1)[arguments]: When building for the Hurd,
add phase 'patch-configure'.
(openssl)[arguments]: And delete it again.
</span></span></td><td>Janneke Nieuwenhuizen</td></tr>
<tr><td><span title='2023-07-20 10:11:33 +0200'>2023-07-20</span></td><td><a href='/guix/commit/gnu/packages/tls.scm?id=378766dd2e7187d8ea48c47dd3fc53a7e66cf5c7'>gnu: openssl: Build fix for the Hurd.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/tls.scm (openssl-3.0)[arguments]: When building on the Hurd,
add "hurd-x86" to #:configure-flags.
</span></span></td><td>Janneke Nieuwenhuizen</td></tr>