diff --git a/include/common/string-helpers.h b/include/common/string-helpers.h
index efa5bfd2..e49fa110 100644
--- a/include/common/string-helpers.h
+++ b/include/common/string-helpers.h
@@ -59,8 +59,7 @@ char *strdup_printf(const char *fmt, ...);
  * The separator is arbitrary. When the separator is NULL, a single space will
  * be used.
  */
-char *str_join(const char *const parts[],
-	const char *restrict fmt, const char *restrict sep);
+char *str_join(const char *const parts[], const char *fmt, const char *sep);
 
 /**
  * str_endswith - indicate whether a string ends with a given suffix
diff --git a/src/common/string-helpers.c b/src/common/string-helpers.c
index f753d1a1..f94e1dd9 100644
--- a/src/common/string-helpers.c
+++ b/src/common/string-helpers.c
@@ -93,8 +93,7 @@ strdup_printf(const char *fmt, ...)
 }
 
 char *
-str_join(const char *const parts[],
-		const char *restrict fmt, const char *restrict sep)
+str_join(const char *const parts[], const char *fmt, const char *sep)
 {
 	assert(parts);