use openssl with md5 instead of gnutls and outdated-vendor-md5
https://bugs.gentoo.org/880535
https://bugs.gentoo.org/898094
--- a/configure.ac
+++ b/configure.ac
@@ -52,12 +52,6 @@ PKG_CHECK_MODULES([CHECK], [check >= 0.9.3], [
     AC_DEFINE([HAVE_CHECK_H], [1], [Has check.h])
   ],:)
 
-PKG_CHECK_MODULES([GNUTLS], [gnutls >= 1.0.0], [
-    AC_DEFINE([HAVE_GNUTLS], [1], [Has gnutls >= 1.0.0])
-    HAVE_GNUTLS=1
-    LIBS="${LIBS} ${GNUTLS_LIBS}"
-    CFLAGS="${CFLAGS} ${GNUTLS_CFLAGS}"
-  ], [
     AC_CHECK_HEADERS([openssl/md5.h], [
       AC_SEARCH_LIBS([MD5_Init], [crypto], [
         AC_DEFINE([HAVE_CRYPTO_WITH_MD5], [1], [The crypto lib has MD5 functions])
@@ -69,7 +63,6 @@ PKG_CHECK_MODULES([GNUTLS], [gnutls >= 1.0.0], [
         AC_DEFINE([HAVE_CRYPTO_WITH_SHA1], [1], [The crpyto lib has SHA1 functions])
       ])
     ])
-])
 PKG_CHECK_MODULES([GNUTLS319], [gnutls >= 3.1.9], [
     AC_DEFINE([HAVE_GNUTLS_319], [1], [Has gntuls >= 3.1.9])
   ],:)