use strtonum to parse the argument to -j in make

[David Gwynne]

i cant remember why i was looking at this, but strtoll annoys me.

ok?

Index: main.c
===================================================================
RCS file: /cvs/src/usr.bin/make/main.c,v
retrieving revision 1.119
diff -u -p -r1.119 main.c
--- main.c      4 Jan 2016 10:59:23 -0000       1.119
+++ main.c      19 Apr 2017 01:39:22 -0000
@@ -310,14 +310,14 @@ MainParseArgs(int argc, char **argv)
                        Lst_AtEnd(&makefiles, optarg);
                        break;
                case 'j': {
-                  char *endptr;
+                       const char *errstr;
 
                        forceJobs = true;
-                       maxJobs = strtol(optarg, &endptr, 0);
-                       if (endptr == optarg) {
+                       maxJobs = strtonum(optarg, 1, INT_MAX, &errstr);
+                       if (errstr != NULL) {
                                fprintf(stderr,
-                                       "make: illegal argument to -j option -- 
%s -- not a number\n",
-                                       optarg);
+                                   "make: illegal argument to -j option"
+                                   " -- %s -- %s\n", optarg, errstr);
                                usage();
                        }
                        record_option(c, optarg);