vcl: better handlig of ldp apis that rely on gnu source

Control use of apis that rely on _GNU_SOURCE being defined with compile
time macro.

Also fixes sendmmsg and recvmmsg which were not probably wrapped.

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I207de23210d4b9dc960bb4289159502760c5614d
diff --git a/src/vcl/ldp.h b/src/vcl/ldp.h
index 8d78ead..327e73c 100644
--- a/src/vcl/ldp.h
+++ b/src/vcl/ldp.h
@@ -23,9 +23,9 @@
 #define LDP_DEBUG_INIT 0
 #endif
 
+#include <vcl/ldp_glibc_socket.h>
 #include <vppinfra/error.h>
 #include <vppinfra/types.h>
-#include <vcl/ldp_glibc_socket.h>
 
 #define LDP_ENV_DEBUG     "LDP_DEBUG"
 #define LDP_ENV_APP_NAME  "LDP_APP_NAME"