This patch fixes SLiM so it really waits for the X server to be ready
before attempting to connect to it.  Indeed, the X server notices that
its parent process has a handler for SIGUSR1, and consequently sends it
SIGUSR1 when it's ready to accept connections.

The problem was that SLiM doesn't pay attention to SIGUSR1.  So in practice,
if X starts slowly, then SLiM gets ECONNREFUSED a couple of time on
/tmp/.X11-unix/X0, then goes on trying to connect to localhost:6000,
where nobody answers; eventually, it times out and tries again on
/tmp/.X11-unix/X0, and finally it shows up on the screen.

Patch by L. Courtès.

--- slim-1.3.6/app.cpp	2014-02-05 15:27:20.000000000 +0100
+++ slim-1.3.6/app.cpp	2014-02-09 22:42:04.000000000 +0100
@@ -119,7 +119,9 @@ void CatchSignal(int sig) {
 	exit(ERR_EXIT);
 }
 
+static volatile int got_sigusr1 = 0;
 void User1Signal(int sig) {
+	got_sigusr1 = 1;
 	signal(sig, User1Signal);
 }
 
@@ -884,6 +886,7 @@ int App::WaitForServer() {
 	int	ncycles	 = 120;
 	int	cycles;
 
+	while (!got_sigusr1);
 	for(cycles = 0; cycles < ncycles; cycles++) {
 		if((Dpy = XOpenDisplay(DisplayName))) {
 			XSetIOErrorHandler(xioerror);
2734de7517f7'>refs</a><a class='active' href='/guix/log/tests/git-authenticate.scm'>log</a><a href='/guix/tree/tests/git-authenticate.scm?id=f65d5e84dead34de889482bc394d2734de7517f7'>tree</a><a href='/guix/commit/tests/git-authenticate.scm?id=f65d5e84dead34de889482bc394d2734de7517f7'>commit</a><a href='/guix/diff/tests/git-authenticate.scm?id=f65d5e84dead34de889482bc394d2734de7517f7'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/git-authenticate.scm'>
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<div class='path'>path: <a href='/guix/log/?id=f65d5e84dead34de889482bc394d2734de7517f7'>root</a>/<a href='/guix/log/tests?id=f65d5e84dead34de889482bc394d2734de7517f7'>tests</a>/<a href='/guix/log/tests/git-authenticate.scm?id=f65d5e84dead34de889482bc394d2734de7517f7'>git-authenticate.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/tests/git-authenticate.scm?id=f65d5e84dead34de889482bc394d2734de7517f7&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-06-20 13:18:11 +0200'>2020-06-20</span></td><td><a href='/guix/commit/tests/git-authenticate.scm?id=7b06781a58326f251c4af6340379d68e3cb98adb'>tests: Skip tests that requires gpg when gpg is unavailable.</a><span class='msg-avail'>...<span class='msg-tooltip'>Partly fixes &lt;https://bugs.gnu.org/41932&gt;.
Reported by Simen Endsjø &lt;simendsjo@gmail.com&gt;.

* tests/git-authenticate.scm ("signed commits, SHA1 signature"): Use
'gpg+git-available?' in skip guard.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-06-16 16:10:46 +0200'>2020-06-16</span></td><td><a href='/guix/commit/tests/git-authenticate.scm?id=1e2b9bf2d4ed4edc9ed70c51f414bb2890074a21'>tests: Move OpenPGP helpers to (guix tests gnupg).</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/git-authenticate.scm (key-id): Remove.
(%ed25519-public-key-file, %ed25519-secret-key-file)
(%ed25519bis-public-key-file, %ed25519bis-secret-key-file)
(read-openpgp-packet, key-fingerprint): Move to...
* guix/tests/gnupg.scm: ... here.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-06-12 18:56:11 +0200'>2020-06-12</span></td><td><a href='/guix/commit/tests/git-authenticate.scm?id=52c529ff20b389eb64ac033586e6b1a5c5d82cb5'>git-authenticate: Disallow SHA1 (and MD5) signatures.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/git-authenticate.scm (commit-signing-key): Add
 #:disallowed-hash-algorithms and honor it.
(authenticate-commit)[recent-commit?]: New variable.
Pass #:disallowed-hash-algorithms to 'commit-signing-key'.
* tests/git-authenticate.scm ("signed commits, SHA1 signature"): New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-06-07 23:10:46 +0200'>2020-06-07</span></td><td><a href='/guix/commit/tests/git-authenticate.scm?id=e78275608065ef073775fabb9f1a757da65851f2'>git-authenticate: Prevent removal of '.guix-authorizations'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/git-authenticate.scm (commit-authorized-keys)
[parents-have-authorizations-file?, assert-parents-lack-authorizations]:
New procedures.
Use the latter before returning DEFAULT-AUTHORIZATIONS.
* guix/git.scm (false-if-git-not-found): Export.
* guix/tests/git.scm (populate-git-repository): Add 'remove' clause.
* tests/git-authenticate.scm ("signed commits, .guix-authorizations removed"):
New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-06-05 22:54:06 +0200'>2020-06-05</span></td><td><a href='/guix/commit/tests/git-authenticate.scm?id=c83eedba2361c3831d3efb5ad63d5077d636fb28'>git-authenticate: Add tests.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/tests/git.scm (call-with-environment-variables)
(with-environment-variables): Remove.
* guix/tests/git.scm (populate-git-repository): Add clauses for signed
commits and signed merges.
* guix/tests/gnupg.scm: New file.
* tests/git-authenticate.scm: New file.
* tests/ed25519bis.key, tests/ed25519bis.sec: New files.
* Makefile.am (dist_noinst_DATA): Add 'guix/tests/gnupg.scm'.
(SCM_TESTS): Add 'tests/git-authenticate.scm'.
(EXTRA_DIST): Add tests/ed25519bis.{key,sec}.
</span></span></td><td>Ludovic Courtès</td></tr>