Add support for OpenSSL 1.1.0 to configure script

OpenSSL 1.1.0 removed the SSLeay() function and replaced it with a macro, that AC_CHECK_LIB can't see.

Search for ERR_get_error() instead.

configure.in

@@ -562,8 +562,8 @@ case "$with_ssl" in
 esac
 case "$with_ssl" in
     yes|check)
-      AC_CHECK_LIB([crypto], [SSLeay], [], [], [])
-      if test x"$ac_cv_lib_crypto_SSLeay" = x"yes"; then
+      AC_CHECK_LIB([crypto], [ERR_get_error], [], [], [])
+      if test x"$ac_cv_lib_crypto_ERR_get_error" = x"yes"; then
         AC_CHECK_LIB([ssl], [SSL_accept], [], [], [])
       fi
       if test x"$ac_cv_lib_ssl_SSL_accept" = x"yes"; then