--- lilypond-2.25.4/lily/all-font-metrics-scheme.cc~	2023-04-22 11:55:50.000000000 -0500
+++ lilypond-2.25.4/lily/all-font-metrics-scheme.cc	2023-05-18 09:46:06.059888398 -0500
@@ -24,7 +24,7 @@
 
 All_font_metrics *all_fonts_global = nullptr;
 // GC-protects the all_fonts_global object.
-SCM all_fonts_global_scm = SCM_UNDEFINED;
+volatile SCM all_fonts_global_scm = SCM_UNDEFINED;
 
 LY_DEFINE (ly_reset_all_fonts, "ly:reset-all-fonts", 0, 0, 0, (),
            R"(