Fix gcc warnings.

src/3rdparty/jansson/dump.c

@@ -5,7 +5,9 @@
  * it under the terms of the MIT license. See LICENSE for details.
  */
 
+#ifdef _MSC_VER
 #pragma warning(disable:4090)
+#endif
 
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE

src/3rdparty/jansson/hashtable.c

@@ -5,7 +5,9 @@
  * it under the terms of the MIT license. See LICENSE for details.
  */
 
+#ifdef _MSC_VER
 #pragma warning(disable:4334)
+#endif
 
 #if HAVE_CONFIG_H
 #include <jansson_private_config.h>

src/net/Network.cpp

@@ -21,7 +21,9 @@
  *   along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifdef _MSC_VER
 #pragma warning(disable:4244)
+#endif
 
 #include <inttypes.h>
 #include <memory>