add a couple of missing #include lines

lib/libcompat/4.3/regex.c

@@ -50,6 +50,7 @@ static char sccsid[] = "@(#)regex.c	5.1 (Berkeley) 3/29/92";
 #include <regexp.h>
 #include <string.h>
 #include <stdlib.h>
+#include <string.h>
 
 static regexp *re_regexp;
 static int re_goterr;

lib/libcompat/4.3/rexec.c

@@ -36,11 +36,13 @@ static char sccsid[] = "@(#)rexec.c	8.1 (Berkeley) 6/4/93";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <sys/socket.h>
 
 #include <netinet/in.h>
 
 #include <stdio.h>
+#include <unistd.h>
 #include <netdb.h>
 #include <errno.h>