Make sure to manually export s3_resume() for old buggy gcc versions.
diff --git a/src/resume.c b/src/resume.c
index 0e27c1c..9db8cad 100644
--- a/src/resume.c
+++ b/src/resume.c
@@ -120,3 +120,7 @@
     }
     call16big(&br);
 }
+
+// Ughh - some older gcc compilers have a bug which causes VISIBLE32
+// functions to not be exported as global variables.
+asm(".global s3_resume");