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);
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<tr><th>author</th><td>Raghav Gururajan &lt;raghavgururajan@disroot.org&gt;</td><td class='right'>2019-12-30 13:37:53 -0500</td></tr>
<tr><th>committer</th><td>Jan Nieuwenhuizen &lt;janneke@gnu.org&gt;</td><td class='right'>2019-12-30 20:57:49 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/guix/commit/?id=304162651aa4785eefdf447b4a9ea771e2a4d06d'>304162651aa4785eefdf447b4a9ea771e2a4d06d</a> (<a href='/guix/patch/?id=304162651aa4785eefdf447b4a9ea771e2a4d06d'>patch</a>)</td></tr>
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<tr><th>parent</th><td colspan='2' class='oid'><a href='/guix/commit/?id=fc4eb87dc45b169e3912c73bbf60cb8ce76b7c7c'>fc4eb87dc45b169e3912c73bbf60cb8ce76b7c7c</a> (<a href='/guix/diff/?id=304162651aa4785eefdf447b4a9ea771e2a4d06d&amp;id2=fc4eb87dc45b169e3912c73bbf60cb8ce76b7c7c'>diff</a>)</td></tr><tr><th>download</th><td colspan='2' class='oid'><a href='/guix/snapshot/guix-304162651aa4785eefdf447b4a9ea771e2a4d06d.tar.gz'>guix-304162651aa4785eefdf447b4a9ea771e2a4d06d.tar.gz</a><br/><a href='/guix/snapshot/guix-304162651aa4785eefdf447b4a9ea771e2a4d06d.zip'>guix-304162651aa4785eefdf447b4a9ea771e2a4d06d.zip</a><br/></td></tr></table>
<div class='commit-subject'>gnu: Add gnome-menus.</div><div class='commit-msg'>* gnu/packages/gnome.scm (gnome-menus). New variable.
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