Reversed the check for udp.h, fixes compilation on Linux.

configure.in

@@ -865,7 +865,7 @@ AC_CHECK_FUNCS(backtrace)
 AC_CHECK_FUNCS(prctl)
 AC_CHECK_FUNCS(gethostbyname_r)
 
-AC_CHECK_HEADERS(net/pfkeyv2.h netipsec/ipsec.h netinet6/ipsec.h netinet/udp.h)
+AC_CHECK_HEADERS(net/pfkeyv2.h netipsec/ipsec.h netinet6/ipsec.h linux/udp.h)
 
 AC_CHECK_MEMBERS([struct sockaddr.sa_len], [], [],
 [

src/charon/plugins/kernel_pfkey/kernel_pfkey_ipsec.c

@@ -37,11 +37,11 @@
 #endif
 
 #ifdef HAVE_NATT
-#ifdef HAVE_NETINET_UDP_H
-#include <netinet/udp.h>
-#else
+#ifdef HAVE_LINUX_UDP_H
 #include <linux/udp.h>
-#endif /*HAVE_NETINET_UDP_H*/
+#else
+#include <netinet/udp.h>
+#endif /*HAVE_LINUX_UDP_H*/
 #endif /*HAVE_NATT*/
 
 #include <unistd.h>