diff --git a/regcomp.c b/regcomp.c
index 6de9b72..1f24938 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -464,7 +464,7 @@ re_compile_fastmap_iter (regex_t *bufp, const re_dfastate_t *init_state,
    the return codes and their meanings.)  */
 
 int
-regcomp (regex_t *__restrict preg, const char *__restrict pattern, int cflags)
+regcomp (regex_t *_Restrict_ preg, const char *_Restrict_ pattern, int cflags)
 {
   reg_errcode_t ret;
   reg_syntax_t syntax = ((cflags & REG_EXTENDED) ? RE_SYNTAX_POSIX_EXTENDED
@@ -523,7 +523,7 @@ weak_alias (__regcomp, regcomp)
    from either regcomp or regexec.   We don't use PREG here.  */
 
 size_t
-regerror (int errcode, const regex_t *__restrict preg, char *__restrict errbuf,
+regerror (int errcode, const regex_t *_Restrict_ preg, char *_Restrict_ errbuf,
 	  size_t errbuf_size)
 {
   const char *msg;