mlogc: Checks if curl supports CURL_SSLVERSION_TLSv1_2 before use it

Seems like curl versions older than 7.34.0 does not have support for
`CURL_SSLVERSION_TLSv1_2'. In this cases, using CURL_SSLVERSION_TLSv1
which was added at version 7.9.2. ModSecurity demands a curl version
newer than 7.15.1.

Author: Felipe Zimmerle

build/find_curl.m4

@@ -66,6 +66,10 @@ if test -n "${curl_path}"; then
     curl_ver=`echo ${CURL_VERSION} | awk -F. '{print (\$ 1 * 1000000) + (\$ 2 * 1000) + \$ 3}'`
     if test "$curl_min_ver" -le "$curl_ver"; then
         AC_MSG_RESULT([yes, $CURL_VERSION])
+	curl_tlsv2_ver=`echo 7.34.0 | awk -F. '{print (\$ 1 * 1000000) + (\$ 2 * 1000) + \$ 3}'`
+	if test "$curl_tlsv2_ver" -le "$curl_ver"; then
+	    CURL_CFLAGS="${CURL_CFLAGS} -DWITH_CURL_SSLVERSION_TLSv1_2"
+	fi
     else
         AC_MSG_RESULT([no, $CURL_VERSION])
         AC_MSG_NOTICE([NOTE: curl library may be too old])

mlogc/mlogc.c

@@ -1218,8 +1218,14 @@ static void logc_init(void)
         curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
         curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, FALSE);
         curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0);
+        /* Seems like CURL_SSLVERSION_TLSv1_2 is not supported on libcurl
+         * < v7.34.0
+         */
+#ifdef WITH_CURL_SSLVERSION_TLSv1_2
         curl_easy_setopt(curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1_2);
-
+#else
+        curl_easy_setopt(curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);
+#endif
         curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 15);
         curl_easy_setopt(curl, CURLOPT_NOSIGNAL, TRUE);
         curl_easy_setopt(curl, CURLOPT_HEADER, TRUE);