From 4828ff91ffa937fa6cb1618fcab550c137e60f15 Mon Sep 17 00:00:00 2001
From: Ricardo Wurmus <rekado@elephly.net>
Date: Thu, 3 Dec 2015 08:32:06 +0100
Subject: [PATCH] gnu: gtk+: Add patch to support GUIX_GTK3_PATH.

* gnu/packages/patches/gtk3-respect-GUIX_GTK3_PATH: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/gtk.scm (gtk+) [source]: Add patch.
[native-search-paths]: Add search path for GUIX_GTK3_PATH.
---
 gnu-system.am                                 |  1 +
 gnu/packages/gtk.scm                          |  9 ++++-
 .../patches/gtk3-respect-GUIX_GTK3_PATH.patch | 38 +++++++++++++++++++
 3 files changed, 46 insertions(+), 2 deletions(-)
 create mode 100644 gnu/packages/patches/gtk3-respect-GUIX_GTK3_PATH.patch

diff --git a/gnu-system.am b/gnu-system.am
index 2c62cc5911..4788bc7ba9 100644
--- a/gnu-system.am
+++ b/gnu-system.am
@@ -507,6 +507,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/guile-relocatable.patch			\
   gnu/packages/patches/guile-rsvg-pkgconfig.patch		\
   gnu/packages/patches/gtk2-respect-GUIX_GTK2_PATH.patch	\
+  gnu/packages/patches/gtk3-respect-GUIX_GTK3_PATH.patch	\
   gnu/packages/patches/gtkglext-disable-disable-deprecated.patch \
   gnu/packages/patches/hop-bigloo-4.0b.patch			\
   gnu/packages/patches/hop-linker-flags.patch			\
diff --git a/gnu/packages/gtk.scm b/gnu/packages/gtk.scm
index d2257825e8..916873b356 100644
--- a/gnu/packages/gtk.scm
+++ b/gnu/packages/gtk.scm
@@ -583,7 +583,8 @@ application suites.")
                                 name "-" version ".tar.xz"))
             (sha256
              (base32
-              "0lp1hn0qydxx03bianzzr0a4maqzsvylrkzr7c3p0050qihwbgjx"))))
+              "0lp1hn0qydxx03bianzzr0a4maqzsvylrkzr7c3p0050qihwbgjx"))
+            (patches (list (search-patch "gtk3-respect-GUIX_GTK3_PATH.patch")))))
    (propagated-inputs
     `(("at-spi2-atk" ,at-spi2-atk)
       ("atk" ,atk)
@@ -642,7 +643,11 @@ application suites.")
                  (loaders.cache (find-files librsvg "^loaders\\.cache$")))
             (wrap-program prog
               `("GDK_PIXBUF_MODULE_FILE" = ,loaders.cache))))
-        %standard-phases))))))
+        %standard-phases))))
+   (native-search-paths
+    (list (search-path-specification
+           (variable "GUIX_GTK3_PATH")
+           (files '("lib/gtk-3.0")))))))
 
 ;;;
 ;;; Guile bindings.
diff --git a/gnu/packages/patches/gtk3-respect-GUIX_GTK3_PATH.patch b/gnu/packages/patches/gtk3-respect-GUIX_GTK3_PATH.patch
new file mode 100644
index 0000000000..66fd2fd1c4
--- /dev/null
+++ b/gnu/packages/patches/gtk3-respect-GUIX_GTK3_PATH.patch
@@ -0,0 +1,38 @@
+This patch makes GTK+ look for additional modules in a list of directories
+specified by the environment variable "GUIX_GTK3_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	2015-09-20 20:09:05.060590217 +0200
++++ b/gtk/gtkmodules.c	2015-09-20 20:10:33.423124833 +0200
+@@ -52,6 +52,7 @@
+ get_module_path (void)
+ {
+   const gchar *module_path_env;
++  const gchar *module_guix_gtk3_path_env;
+   const gchar *exe_prefix;
+   gchar *module_path;
+   gchar *default_dir;
+@@ -61,6 +62,7 @@
+     return result;
+ 
+   module_path_env = g_getenv ("GTK_PATH");
++  module_guix_gtk3_path_env = g_getenv ("GUIX_GTK3_PATH");
+   exe_prefix = g_getenv ("GTK_EXE_PREFIX");
+ 
+   if (exe_prefix)
+@@ -68,7 +70,13 @@
+   else
+     default_dir = g_build_filename (_gtk_get_libdir (), "gtk-3.0", NULL);
+ 
+-  if (module_path_env)
++  if (module_guix_gtk3_path_env && module_path_env)
++    module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
++				module_guix_gtk3_path_env, module_path_env, default_dir, NULL);
++  else if (module_guix_gtk3_path_env)
++    module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
++				module_guix_gtk3_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);
+   else