hwloc-calc: improve --cpukind parsing

Assume it's a number only if it starts with a digit.
Error-out otherwise, so that things like foo:bar instead of foo=bar are rejected.

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>

Author: bgoglin

utils/hwloc/hwloc-calc.c

@@ -399,8 +399,11 @@ int main(int argc, char *argv[])
         cpukind_infoname = argv[1];
         cpukind_infovalue = equal+1;
         *equal = 0;
-      } else {
+      } else if (argv[1][0] >= '0' && argv[1][0] <= '9') {
         cpukind_index = atoi(argv[1]);
+      } else {
+        fprintf(stderr, "Failed to recognize --cpukind argument %s\n", argv[1]);
+        return EXIT_FAILURE;
       }
       opt = 1;
       goto next_config;