Merge pull request #2172 from keith-dev/v1.x

example.cpp failes to build on FreeBSD

include/spdlog/details/udp_client.h

@@ -14,6 +14,7 @@
 #include <spdlog/details/os.h>
 
 #include <sys/socket.h>
+#include <netinet/in.h>
 #include <arpa/inet.h>
 #include <unistd.h>
 #include <netdb.h>
@@ -90,4 +91,4 @@ public:
     }
 };
 } // namespace details
-} // namespace spdlog
+} // namespace spdlog