fix core:c/libc.errno link_name for Linux and FreeBSD

Although the FreeBSD link matches Darwin, its EILSEQ still matches Linux.

Confirmed with the following program:

```odin
package main
import "core:c/libc"

main :: proc() {
	libc.printf("%d\n", libc.errno()^) // 0
	_ = libc.fopen("nonexistent file", "r")
	libc.printf("%d\n", libc.errno()^) // 2
}
```

on Linux:

	Odin: dev-2022-10:075040ae
	OS:   Manjaro Linux, Linux 5.10.147-1-MANJARO
	CPU:  Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
	RAM:  15953 MiB

and FreeBSD:

	Odin: dev-2022-10:075040ae
	OS:   FreeBSD: Unknown
	CPU:  Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
	RAM:  990 MiB

FreeBSD uname -r: 13.0-RELEASE

0 files changed, 0 insertions, 0 deletions