diff --git a/libc/regex/regerror.c b/libc/regex/regerror.c
index 894a939..838ec8f 100644
--- a/libc/regex/regerror.c
+++ b/libc/regex/regerror.c
@@ -78,7 +78,7 @@
 size_t
 regerror(int errcode, const regex_t *preg, char *errbuf, size_t errbuf_size)
 {
-	struct rerr *r;
+	const struct rerr *r;
 	size_t len;
 	int target = errcode &~ REG_ITOA;
 	char *s;
@@ -117,7 +117,7 @@
 static char *
 regatoi(const regex_t *preg, char *localbuf, int localbufsize)
 {
-	struct rerr *r;
+	const struct rerr *r;
 
 	for (r = rerrs; r->code != 0; r++)
 		if (strcmp(r->name, preg->re_endp) == 0)