From 3a2e56e6855b36ca4fe1e086c3eed89ec2c4af31 Mon Sep 17 00:00:00 2001
From: Jean Boussier <jean.boussier@gmail.com>
Date: Mon, 5 May 2025 15:00:02 +0200
Subject: [PATCH] Fix `USE_MN_THREADS=0` builds on macOS

This was recently broken.
---
 vm_dump.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/vm_dump.c b/vm_dump.c
index 1e4fe976f9..592de8aa58 100644
--- a/vm_dump.c
+++ b/vm_dump.c
@@ -515,9 +515,13 @@ rb_vmdebug_thread_dump_state(FILE *errout, VALUE self)
 static bool
 is_coroutine_start(unw_word_t ip)
 {
+#if USE_MN_THREADS
     struct coroutine_context;
     extern void ruby_coroutine_start(struct coroutine_context *, struct coroutine_context *);
     return ((void *)(ip) == (void *)ruby_coroutine_start);
+#else
+    return false;
+#endif
 }
 #  endif