Standard integer types are uintXX_t not u_intXX_t

This fixes the build with the musl C library.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

diff -durN dvblast-3.0.orig/dvblast.h dvblast-3.0/dvblast.h
--- dvblast-3.0.orig/dvblast.h	2015-10-05 17:51:14.000000000 +0200
+++ dvblast-3.0/dvblast.h	2015-10-30 16:29:25.586125193 +0100
@@ -49,10 +49,10 @@
  * Raw udp packet structure with flexible-array payload
  *****************************************************************************/
 struct udpheader { // FAVOR_BSD hell ...
-  u_int16_t source;
-  u_int16_t dest;
-  u_int16_t len;
-  u_int16_t check;
+  uint16_t source;
+  uint16_t dest;
+  uint16_t len;
+  uint16_t check;
 };
 
 #if defined(__FreeBSD__) || defined(__APPLE__)