crypto/gc: Use 'restrict'.

* lib/gc.h (gc_pbkdf2_hmac, gc_pbkdf2_sha1): Use 'restrict'.
* m4/gc.m4 (gl_GC): Require AC_C_RESTRICT.

3 files changed, 9 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index e62e1aa3fb..5b5b35d227 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2020-02-23  Bruno Haible  <bruno@clisp.org>
 
+	crypto/gc: Use 'restrict'.
+	* lib/gc.h (gc_pbkdf2_hmac, gc_pbkdf2_sha1): Use 'restrict'.
+	* m4/gc.m4 (gl_GC): Require AC_C_RESTRICT.
+
 	crypto/hmac-*: Use 'restrict'.
 	* lib/hmac.h (hmac_md5, hmac_sha1, hmac_sha256, hmac_sha512): Use
 	'restrict'.
diff --git a/lib/gc.h b/lib/gc.h
index 05fb8a3d25..87acdbc5eb 100644
--- a/lib/gc.h
+++ b/lib/gc.h
@@ -185,12 +185,12 @@ extern Gc_rc
 gc_pbkdf2_hmac (Gc_hash hash,
                 const char *P, size_t Plen,
                 const char *S, size_t Slen,
-                unsigned int c, char *DK, size_t dkLen);
+                unsigned int c, char *restrict DK, size_t dkLen);
 
 extern Gc_rc
 gc_pbkdf2_sha1 (const char *P, size_t Plen,
                 const char *S, size_t Slen,
-                unsigned int c, char *DK, size_t dkLen);
+                unsigned int c, char *restrict DK, size_t dkLen);
 
 /*
   TODO:
diff --git a/m4/gc.m4 b/m4/gc.m4
index 0180d32b78..7f8f462714 100644
--- a/m4/gc.m4
+++ b/m4/gc.m4
@@ -1,4 +1,4 @@
-# gc.m4 serial 12
+# gc.m4 serial 13
 dnl Copyright (C) 2005-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -25,4 +25,6 @@ AC_DEFUN([gl_GC],
     fi
   fi
   AC_SUBST([LIB_CRYPTO])
+
+  AC_REQUIRE([AC_C_RESTRICT])
 ])