gst_all_1.gst-rtsp-server: fix pkgconfig includedir and libdir

pkgs/development/libraries/gstreamer/rtsp-server/default.nix

@@ -20,6 +20,15 @@ stdenv.mkDerivation rec {
 
   outputs = [ "out" "dev" ];
 
+  patches = [
+    # To use split outputs, we need this so double prefix won't be used in the
+    # pkg-config files. Hopefully, this won't be needed on the next release,
+    # _if_
+    # https://gitlab.freedesktop.org/gstreamer/gst-rtsp-server/merge_requests/1
+    # will be merged. For the current release, this merge request won't apply.
+    ./fix_pkgconfig_includedir.patch
+  ];
+
   nativeBuildInputs = [
     meson
     ninja

pkgs/development/libraries/gstreamer/rtsp-server/fix_pkgconfig_includedir.patch

@@ -0,0 +1,15 @@
+diff --git i/pkgconfig/meson.build w/pkgconfig/meson.build
+index 8ed8299..594cbfe 100644
+--- i/pkgconfig/meson.build
++++ w/pkgconfig/meson.build
+@@ -2,8 +2,8 @@ pkgconf = configuration_data()
+ 
+ pkgconf.set('prefix', get_option('prefix'))
+ pkgconf.set('exec_prefix', '${prefix}')
+-pkgconf.set('libdir', '${prefix}/@0@'.format(get_option('libdir')))
+-pkgconf.set('includedir', '${prefix}/@0@'.format(get_option('includedir')))
++pkgconf.set('libdir', join_paths(get_option('prefix'), get_option('libdir')))
++pkgconf.set('includedir', join_paths(get_option('prefix'), get_option('includedir')))
+ pkgconf.set('GST_API_VERSION', api_version)
+ pkgconf.set('VERSION', gst_version)
+