Fixed some include file problems on Windows reported by David Rosenstrauch

lib/krb5.c

@@ -62,6 +62,9 @@
 #include "krb4.h"
 #include "memory.h"
 
+#define _MPRINTF_REPLACE /* use our functions only */
+#include <curl/mprintf.h>
+
 /* The last #include file should be: */
 #include "memdebug.h"
 

lib/security.c

@@ -51,7 +51,10 @@
 
 #include <stdlib.h>
 #include <string.h>
+
+#ifdef HAVE_NETDB_H
 #include <netdb.h>
+#endif
 
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>