This patch provides an update so that nhc98 can be built and works with
a modern C compiler (GCC 11) and libc (glibc 2.33).

diff --git a/Makefile.inc b/Makefile.inc
index 4fbd47a..5bce5c9 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -1,6 +1,10 @@
 ### Configurable variables:
 
-OPT = -O3
+# We want C89 semantics plus C++-style comments and things like the
+# 'setjmp_buf' and 'u_short' types.  More importantly, build with '-O1'
+# only to avoid modern optimizations that break the code.
+OPT = -O1 -std=gnu89 -D_GNU_SOURCE=1
+
 #ARCH = -m32
 ARCH = 
 
diff --git a/script/nhc98heap.c b/script/nhc98heap.c
index 534010e..a30d5cd 100644
--- a/script/nhc98heap.c
+++ b/script/nhc98heap.c
@@ -1,5 +1,6 @@
 #include <stdlib.h>
 #include <stdio.h>
+#include <ctype.h>
 main(int argc, char **argv)
 {
   int prefix = 1;
diff --git a/src/runtime/Kernel/collector.c b/src/runtime/Kernel/collector.c
index b95a273..1f879c5 100644
--- a/src/runtime/Kernel/collector.c
+++ b/src/runtime/Kernel/collector.c
@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <unistd.h>
 #include "node.h"
 /*#include "newmacros.h"  -- already included in node.h */
 /*#include "runtime.h"    -- already included in node.h */
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<div class='path'>path: <a href='/guix/log/?id=18d6173214eb82781b36d041bab99494c653f979'>root</a>/<a href='/guix/log/tests?id=18d6173214eb82781b36d041bab99494c653f979'>tests</a>/<a href='/guix/log/tests/guix-shell.sh?id=18d6173214eb82781b36d041bab99494c653f979'>guix-shell.sh</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/guix-shell.sh?id=18d6173214eb82781b36d041bab99494c653f979&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-04-21 16:16:38 +0200'>2023-04-21</span></td><td><a href='/guix/commit/tests/guix-shell.sh?id=37dd69b44511dc73eb04bdebe8d82c9a0386338e'>tests: Fix checks for expected failures.</a><span class='msg-avail'>...</span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2022-11-15 14:15:11 -0500'>2022-11-15</span></td><td><a href='/guix/commit/tests/guix-shell.sh?id=b31ea797edb4f6e8c14e8fe790da1319607c5cb1'>guix: shell: Add '--symlink' option.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2022-09-04 23:10:10 +0200'>2022-09-04</span></td><td><a href='/guix/commit/tests/guix-shell.sh?id=7a2acbdc5a9eed7c5dc3fe947f54fbebd89c0892'>store: Open daemon connections with SOCK_CLOEXEC.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-02-18 14:14:38 +0100'>2022-02-18</span></td><td><a href='/guix/commit/tests/guix-shell.sh?id=5a57313918a5c1bd5cf8238c2dcae64a03523952'>profiles: 'profile-derivation' rejects unsupported packages.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-12-10 21:49:25 +0100'>2021-12-10</span></td><td><a href='/guix/commit/tests/guix-shell.sh?id=32750e8c3ed38df4cafb39cffa878c6851abc899'>Merge remote-tracking branch 'signed/master' into core-updates</a></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2021-12-10 15:32:44 +0100'>2021-12-10</span></td><td><a href='/guix/commit/tests/guix-shell.sh?id=71977101218d1fd5d7f5016cbbcb8710be057d49'>shell: When using '-D -f', '-D' has no effect on remaining packages.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-11-18 22:59:40 +0100'>2021-11-18</span></td><td><a href='/guix/commit/tests/guix-shell.sh?id=3ad135625b7c33f9c680943a6b79e4593c308249'>shell: Adjust test to expect C_INCLUDE_PATH, not CPATH.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-10-30 19:12:40 +0200'>2021-10-30</span></td><td><a href='/guix/commit/tests/guix-shell.sh?id=98173af5222ab5e879e44ba9521dec5416ba8c60'>shell: Error out when an unauthorized guix.scm/manifest.scm is found.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-10-25 19:02:23 +0200'>2021-10-25</span></td><td><a href='/guix/commit/tests/guix-shell.sh?id=746584e0ca200e7bf51b139ceb36c19ea81d6ef1'>shell: By default load the local 'manifest.scm' or 'guix.scm' file.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-10-25 18:58:18 +0200'>2021-10-25</span></td><td><a href='/guix/commit/tests/guix-shell.sh?id=80edb7df6586464aa40e84e103f0045452de95db'>Add 'guix shell'.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>