Fix small matters and improve sysconf()

- Fix mkdeps.com out of memory error
- Remove static memory from __get_cpu_count()
- Add support for passing hyphen to cat in cocmd
- Change more ZipOS errors from ENOTSUP to EROFS
- Specify mem_unit in sysinfo() output on BSD OSes

test/libc/calls/sched_getaffinity_test.c

@@ -51,7 +51,7 @@ TEST(sched_getaffinity, firstOnly) {
 }
 
 TEST(sched_getaffinity, secondOnly) {
-  if (_getcpucount() < 2) return;
+  if (__get_cpu_count() < 2) return;
   cpu_set_t x, y;
   CPU_ZERO(&x);
   CPU_SET(1, &x);