1 files changed, 76 insertions, 0 deletions
diff --git a/m4/gl-openssl.m4 b/m4/gl-openssl.m4
new file mode 100644
index 0000000..d076f84
--- /dev/null
+++ b/m4/gl-openssl.m4
@@ -0,0 +1,76 @@
+# gl-openssl.m4 serial 6
+dnl Copyright (C) 2013-2022 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_SET_CRYPTO_CHECK_DEFAULT],
+[
+  m4_define([gl_CRYPTO_CHECK_DEFAULT], [$1])
+])
+gl_SET_CRYPTO_CHECK_DEFAULT([no])
+
+AC_DEFUN([gl_CRYPTO_CHECK],
+[
+  dnl gnulib users set this before gl_INIT with gl_SET_CRYPTO_CHECK_DEFAULT()
+  m4_divert_once([DEFAULTS], [with_openssl_default='gl_CRYPTO_CHECK_DEFAULT'])
+
+  dnl Only clear once, so crypto routines can be checked for individually
+  m4_divert_once([DEFAULTS], [LIB_CRYPTO=])
+
+  AC_ARG_WITH([openssl],
+    [[  --with-openssl[=ARG]    use libcrypto hash routines for the hash functions
+                          MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512.
+                          Valid ARGs are:
+                            'yes',
+                            'no',
+                            'auto' => use if any version available,
+                            'auto-gpl-compat' => use if GPL compatible version
+                                                 available,
+                            'optional' => use if available
+                                          and warn if not available;
+                          Default is ']gl_CRYPTO_CHECK_DEFAULT['.]m4_ifdef([gl_AF_ALG], [
+                          Note also --with-linux-crypto, which will enable the
+                          use of Linux kernel crypto routines (if available),
+                          which has precedence for files.])],
+    [],
+    [with_openssl=$with_openssl_default])
+
+  AC_SUBST([LIB_CRYPTO])
+  if test "x$with_openssl" != xno; then
+    if test "x$with_openssl" = xauto-gpl-compat; then
+      AC_CACHE_CHECK([whether openssl is GPL compatible],
+                     [gl_cv_openssl_gpl_compat],
+        [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM([[
+                #include <openssl/opensslv.h>
+                #if OPENSSL_VERSION_MAJOR < 3
+                  #error "openssl >= version 3 not found"
+                #endif
+              ]])],
+           [gl_cv_openssl_gpl_compat=yes],
+           [gl_cv_openssl_gpl_compat=no])])
+    fi
+    if test "x$with_openssl" != xauto-gpl-compat ||
+       test "x$gl_cv_openssl_gpl_compat" = xyes; then
+      AC_CHECK_LIB([crypto], [$1],
+        [AC_CHECK_HEADERS(
+           m4_if([$1], [MD5], [openssl/md5.h], [openssl/sha.h]),
+           [LIB_CRYPTO=-lcrypto
+            AC_DEFINE([HAVE_OPENSSL_$1], [1],
+              [Define to 1 if libcrypto is used for $1.])])])
+    fi
+    if test "x$LIB_CRYPTO" = x; then
+      message='openssl development library not found for $1.
+  If you want to install it, first find the pre-built package name:
+    - On Debian and Debian-based systems: libssl-dev,
+    - On Red Hat distributions: openssl-devel.
+    - Other: https://repology.org/project/openssl/versions'
+      if test "x$with_openssl" = xyes; then
+        AC_MSG_ERROR([$message])
+      elif test "x$with_openssl" = xoptional; then
+        AC_MSG_WARN([$message])
+      fi
+    fi
+  fi
+])