Workaround for PATH_MAX usage on the Hurd.

Taken from https://salsa.debian.org/debian/screen/-/blob/master/debian/patches/61-default-PATH_MAX-if-undefined-for-hurd.patch

Description: Set PATH_MAX to 4096 if undefined
 Fixes FTBFS since 4.4.0 on GNU/Hurd. Updated to add one more occurrence for 4.5.0.
Author: Axel Beckert <abe@debian.org>
Bug: https://savannah.gnu.org/bugs/?50089
Last-Updated: 2017-01-18

--- a/tty.sh
+++ b/tty.sh
@@ -1478,6 +1478,13 @@
   return 0;
 }
 
+/*
+ * Define PATH_MAX to 4096 if it's not defined, like on GNU/Hurd
+ */
+
+#ifndef PATH_MAX
+#define PATH_MAX 4096
+#endif
 
 int CheckTtyname (char *tty)
 {
--- a/screen.h
+++ b/screen.h
@@ -109,6 +109,13 @@
 # define DEFAULT_BUFFERFILE	"/tmp/screen-exchange"
 #endif
 
+/*
+ * Define PATH_MAX to 4096 if it's not defined, like on GNU/Hurd
+ */
+
+#ifndef PATH_MAX
+#define PATH_MAX 4096
+#endif
 
 #if defined(hpux) && !(defined(VSUSP) && defined(VDSUSP) && defined(VWERASE) && defined(VLNEXT))
 # define HPUX_LTCHARS_HACK
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<div class='path'>path: <a href='/guix/log/?id=549e0f2fa7f0a19801f6a86c992f1dd48e6b0d0a'>root</a>/<a href='/guix/log/tests?id=549e0f2fa7f0a19801f6a86c992f1dd48e6b0d0a'>tests</a>/<a href='/guix/log/tests/store-roots.scm?id=549e0f2fa7f0a19801f6a86c992f1dd48e6b0d0a'>store-roots.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/store-roots.scm?id=549e0f2fa7f0a19801f6a86c992f1dd48e6b0d0a&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-08-18 16:10:08 +0200'>2023-08-18</span></td><td><a href='/guix/commit/tests/store-roots.scm?id=4b1fdd44ed87dc07d23cc9313a8b6b14d0646923'>tests: store-roots: Remove bogus test.</a><span class='msg-avail'>...<span class='msg-tooltip'>This test was added in 1261ce15233cbf7e24de9959df86a23b46314a28 but it
proved to be bogus: &lt;https://issues.guix.gnu.org/64760&gt;.

* tests/store-roots.scm ("gc-roots, initial"): Remove.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-06-18 23:36:25 +0200'>2023-06-18</span></td><td><a href='/guix/commit/tests/store-roots.scm?id=1261ce15233cbf7e24de9959df86a23b46314a28'>store: Tolerate non-existent GC root directories.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/store/roots.scm (gc-roots): Wrap 'scandir*' call in 'catch'.
* tests/store-roots.scm ("gc-roots, initial"): New test.  Move
'open-connection' call below.
</span></span></td><td>Ludovic Courtès</td></tr>