https://bugs.gentoo.org/978762
https://github.com/uim/uim/issues/207
https://github.com/uim/sigscheme/pull/21
--- a/sigscheme/src/module-sscm-ext.c
+++ b/sigscheme/src/module-sscm-ext.c
@@ -233,7 +233,7 @@ scm_require_internal(const char *filename)
 }
 
 SCM_EXPORT ScmObj
-scm_p_require(ScmObj filename)
+scm_p_require(volatile ScmObj filename)
 {
 #if SCM_COMPAT_SIOD
     ScmObj loaded_str, retsym;