This is copied from NixOS, which is under MIT licence.
https://github.com/NixOS/nixpkgs/blob/master/pkgs/desktops/gnome/misc/gpaste/
--- a/src/gnome-shell/extension.js
+++ b/src/gnome-shell/extension.js
@@ -6,6 +6,8 @@
 
 const Config = imports.misc.config;
 
+imports.gi.GIRepository.Repository.prepend_search_path('@typelibPath@');
+
 imports.gi.versions.Clutter = Config.LIBMUTTER_API_VERSION;
 imports.gi.versions.GLib = '2.0';
 imports.gi.versions.GPaste = '1.0';
--- a/src/gnome-shell/prefs.js
+++ b/src/gnome-shell/prefs.js
@@ -6,6 +6,8 @@
 
 const Gettext = imports.gettext;
 
+imports.gi.GIRepository.Repository.prepend_search_path('@typelibPath@');
+
 //const { GPaste } = imports.gi;
 
 const ExtensionUtils = imports.misc.extensionUtils;
'koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
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<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
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<div class='path'>path: <a href='/guix/log/?id=6fd7e0cc6f4601f3add30e78cae007b909bd6b0c'>root</a>/<a href='/guix/log/gnu?id=6fd7e0cc6f4601f3add30e78cae007b909bd6b0c'>gnu</a>/<a href='/guix/log/gnu/packages?id=6fd7e0cc6f4601f3add30e78cae007b909bd6b0c'>packages</a>/<a href='/guix/log/gnu/packages/mes.scm?id=6fd7e0cc6f4601f3add30e78cae007b909bd6b0c'>mes.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/mes.scm?id=6fd7e0cc6f4601f3add30e78cae007b909bd6b0c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-06-13 13:00:36 +0200'>2019-06-13</span></td><td><a href='/guix/commit/gnu/packages/mes.scm?id=b8016467273d06ffe3780ac97d38acfd72ce15d9'>gnu: nyacc: Add 0.94.0.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-05-21 16:41:42 +0200'>2019-05-21</span></td><td><a href='/guix/commit/gnu/packages/mes.scm?id=0a01bb55a642e80f20278226d94f5c9046bee4c2'>gnu: mes: Prepare for non-x86 architectures.</a><span class='msg-avail'>...</span></td><td>Danny Milosavljevic</td></tr>
<tr><td><span title='2018-12-16 19:58:31 +0100'>2018-12-16</span></td><td><a href='/guix/commit/gnu/packages/mes.scm?id=504d9fcb8599870a7430eac693ff26615f4b7d6e'>gnu: mes: Update to 0.19.</a><span class='msg-avail'>...</span></td><td>Jan Nieuwenhuizen</td></tr>