<limits.h> is necessary for using INT_MIN, so included it here

explicitly rather than relying on name space pollution to pull it in
for us.

NB: The usage of INT_MIN is somewhat bogus and suspect to my eye, but this
commit doesn't address that issue.

usr.bin/make/arch.c

@@ -94,6 +94,7 @@ __FBSDID("$FreeBSD$");
 #include <ctype.h>
 #include <errno.h>
 #include <inttypes.h>
+#include <limits.h>
 #include <regex.h>
 #include <stdlib.h>
 #include <stdio.h>