Merge pull request #1 from yshl/gc-7.1

cannot built the master branch with gc-7.1

main.c

@@ -419,7 +419,11 @@ main(int argc, char **argv, char **envp)
     char **getimage_args = NULL;
 #endif /* defined(DONT_CALL_GC_AFTER_FORK) && defined(USE_IMAGE) */
     GC_INIT();
+#if (GC_VERSION_MAJOR>=7) && (GC_VERSION_MINOR>=2)
     GC_set_oom_fn(die_oom);
+#else
+    GC_oom_fn = die_oom;
+#endif
 #if defined(ENABLE_NLS) || (defined(USE_M17N) && defined(HAVE_LANGINFO_CODESET))
     setlocale(LC_ALL, "");
 #endif