diff --git a/mjit.c b/mjit.c
index 78c50d10d5..aef4bd2fc8 100644
--- a/mjit.c
+++ b/mjit.c
@@ -416,10 +416,10 @@ init_header_filename(void)
             verbose(3, "PRELOADENV("PRELOADENV")=%s", getenv(PRELOADENV));
             /* assume no other PRELOADENV in test-all */
             unsetenv(PRELOADENV);
+            verbose(3, "MJIT_HEADER: %s", hdr);
+            header_file = ruby_strdup(hdr);
+            if (!header_file) return FALSE;
         }
-        verbose(3, "MJIT_HEADER: %s", hdr);
-        header_file = ruby_strdup(hdr);
-        if (!header_file) return FALSE;
     }
     else
 #endif