Based on the upstream fix for the java8 compilation issue.
Simplified patch.
Upstream version of patch does not work with this source tree.

The issue is that in java8 it is an error to pass null to
removeAll. Results in null pointer exception. java7
behaviour was to return the list unmodified.

From 43867d50c05d1c06ab7220eb974a8874ae10c308 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A1bor=20Boskovits?= <boskovits@gmail.com>
Date: Fri, 5 Jan 2018 19:08:24 +0100
Subject: [PATCH] Fix java8 complilation error.

---
 tool/src/main/java/org/antlr/tool/CompositeGrammar.java | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tool/src/main/java/org/antlr/tool/CompositeGrammar.java b/tool/src/main/java/org/antlr/tool/CompositeGrammar.java
index f34ea73..63740a6 100644
--- a/tool/src/main/java/org/antlr/tool/CompositeGrammar.java
+++ b/tool/src/main/java/org/antlr/tool/CompositeGrammar.java
@@ -226,7 +226,9 @@ public class CompositeGrammar {
 	public List<Grammar> getIndirectDelegates(Grammar g) {
 		List<Grammar> direct = getDirectDelegates(g);
 		List<Grammar> delegates = getDelegates(g);
-		delegates.removeAll(direct);
+		if(direct != null) {
+		        delegates.removeAll(direct);
+		}
 		return delegates;
 	}
 
-- 
2.15.1

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<tr><td><span title='2023-07-20 10:11:26 +0200'>2023-07-20</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=d4306847bf8736bf60a2ff435fd2d8ef763f769c'>Revert "gnu: libunistring: Fix make check for the Hurd."</a><span class='msg-avail'>...<span class='msg-tooltip'>This reverts commit 12e6a5923812abf180f03bea9e07dd99244a3fcd, which used
XFAIL_TESTS to have 'make check' pass with failing tests "test-perror2"
"test-strerror_r" that now pass with glibc-2.37 and libc-for-target in
commencement.
</span></span></td><td>Janneke Nieuwenhuizen</td></tr>
<tr><td><span title='2023-05-31 07:51:28 +0200'>2023-05-31</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=12e6a5923812abf180f03bea9e07dd99244a3fcd'>gnu: libunistring: Fix make check for the Hurd.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/libunistring.scm (libunistring)[arguments]: Set XFAIL_TESTS
with test-perror2, and test-strerror_r when building to the Hurd.
</span></span></td><td>Janneke Nieuwenhuizen</td></tr>
<tr><td><span title='2022-05-28 22:01:09 +0300'>2022-05-28</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=3acb615a3828207d55f52873b669c6917a16e10d'>gnu: libunistring: Rewrite using gexps.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/libunistring.scm (libunistring)[arguments]: Rewrite using
gexps. Remove trailing #t.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2022-05-28 22:01:09 +0300'>2022-05-28</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=e7fa95dc46e984cdd3b47d89405b8ba304e73dec'>gnu: libunistring: Update to 1.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/libunistring.scm (libunistring): Update to 1.0.
[license]: Update in accordance with upstream.
</span></span></td><td>Efraim Flashner</td></tr>