pfkey: Always include stdint.h

On some systems (e.g. on Debian/kFreeBSD) that header is required when
including ipsec.h, on Linux we require it too when including pfkeyv2.h,
so to simplify things we just always include it.

src/libhydra/plugins/kernel_pfkey/kernel_pfkey_ipsec.c

@@ -35,6 +35,7 @@
  * THE SOFTWARE.
  */
 
+#include <stdint.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 
@@ -45,7 +46,6 @@
 #ifdef HAVE_NET_PFKEYV2_H
 #include <net/pfkeyv2.h>
 #else
-#include <stdint.h>
 #include <linux/pfkeyv2.h>
 #endif