2023-09-01 Bruno Haible <br...@clisp.org>
crypto/{sha*,md5}-buffer: Add comment.
* m4/gl-openssl.m4 (gl_CRYPTO_CHECK): Add comment regarding license.
diff --git a/m4/gl-openssl.m4 b/m4/gl-openssl.m4
index 7eab4e102e..637803b814 100644
--- a/m4/gl-openssl.m4
+++ b/m4/gl-openssl.m4
@@ -1,4 +1,4 @@
-# gl-openssl.m4 serial 6
+# gl-openssl.m4 serial 7
dnl Copyright (C) 2013-2023 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -39,6 +39,9 @@ AC_DEFUN([gl_CRYPTO_CHECK]
AC_SUBST([LIB_CRYPTO])
if test "x$with_openssl" != xno; then
if test "x$with_openssl" = xauto-gpl-compat; then
+ dnl OpenSSL versions < 3 are under the OpenSSL license, which is not
+ dnl GPL compatible.
+ dnl See <https://www.gnu.org/licenses/license-list.en.html#OpenSSL>.
AC_CACHE_CHECK([whether openssl is GPL compatible],
[gl_cv_openssl_gpl_compat],
[AC_COMPILE_IFELSE(
