Lookup gzdoom pk3 files in the installed directory in
addition to the path that is stored in ~/.config/gzdoom/.

Simply replacing the hardcoded /usr/share would leave the
configfile pointing to outdated guix builds, which could get
garbage collected and break the gzdoom installation.
This ensures that the files installed with the corresponding
build will be used.

--- /src/d_main.cpp	2018-01-16 22:13:09.700602781 +0200
+++ /src/d_main.cpp	2018-01-16 22:22:36.560617961 +0200
@@ -1716,6 +1716,11 @@
 		return wad;
 	}
 
+    mysnprintf (wad, countof(wad), "%s/%s", GUIX_OUT_PK3, file);
+    if (DirEntryExists (wad)) {
+        return wad;
+    }
+
 	if (GameConfig != NULL && GameConfig->SetSection ("FileSearch.Directories"))
 	{
 		const char *key;
rm.submit();'>
<option value='koszko' selected='selected'>koszko</option>
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<div class='path'>path: <a href='/guix/log/?id=9de76735dba9f4c44a51e755e2db472cdb528d49'>root</a>/<a href='/guix/log/gnu?id=9de76735dba9f4c44a51e755e2db472cdb528d49'>gnu</a>/<a href='/guix/log/gnu/packages?id=9de76735dba9f4c44a51e755e2db472cdb528d49'>packages</a>/<a href='/guix/log/gnu/packages/autotools.scm?id=9de76735dba9f4c44a51e755e2db472cdb528d49'>autotools.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/autotools.scm?id=9de76735dba9f4c44a51e755e2db472cdb528d49&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-05-13 09:30:26 +0300'>2020-05-13</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=3c986a7dc268756c097212de958f046b29b76c1b'>mailmap: Update entries for Nikita.</a><span class='msg-avail'>...</span></td><td>nikita</td></tr>
<tr><td><span title='2020-04-23 07:28:02 +0200'>2020-04-23</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=d64a6d267db7643edb6c9a76a830be08e147127b'>gnu: automake: Support cross-build.</a><span class='msg-avail'>...</span></td><td>Jan (janneke) Nieuwenhuizen</td></tr>
<tr><td><span title='2020-04-23 07:18:47 +0200'>2020-04-23</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=b085d43633d28b1810b7bc74f8dff25717056420'>gnu: autoconf: Support cross-build.</a><span class='msg-avail'>...</span></td><td>Jan (janneke) Nieuwenhuizen</td></tr>
<tr><td><span title='2020-03-27 00:21:10 +0100'>2020-03-27</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=20586ffdc746b17f8208e77852752e99bf5bee55'>gnu: Automake: Remove version 1.16.1.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-03-27 00:12:15 +0100'>2020-03-27</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=18af6870370226b4d502d7372844e7f2aded5887'>Merge branch 'master' into core-updates</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-03-24 18:03:18 +0100'>2020-03-24</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=72a5cc53586080e75ae4ee80f3a2467ff30c4f5e'>gnu: automake: Add version 1.16.2.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-03-14 13:13:40 +0100'>2020-03-14</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=961d2ee2695b38503b463d055e9c7edbcc0bf307'>Merge branch 'master' into core-updates</a></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-03-13 05:36:09 +0100'>2020-03-13</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=2eed6813b6a447524fad8c29412a1efc8c135456'>gnu: autobuild: Use HTTPS home page.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2020-03-04 23:16:17 +0100'>2020-03-04</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=ebb7cf9e21060105d9950dd5142c0eb918083666'>Merge branch 'master' into core-updates</a></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-02-16 22:54:47 +0100'>2020-02-16</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=25ee4a474511162e3ad98e7ecb0d06cedf438b0f'>gnu: autoconf: Use HTTPS home page.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-09-24 08:14:15 +0200'>2019-09-24</span></td><td><a href='/guix/commit/gnu/packages/autotools.scm?id=647cfcf68184e8558fcea751ef6d95b6e5d86ae1'>gnu: libtool: Fix cross-compilation.</a><span class='msg-avail'>...</span></td><td>Pierre-Moana Levesque</td></tr>