Rollup merge of #130248 - nyurik:fix-129895, r=workingjubilee

Limit `libc::link` usage to `nto70` target only, not NTO OS

It seems QNX 7.0 does not support `linkat` at all (most tests were failing). Limiting to QNX 7.0 only, while using `linkat` for the future versions seems like the right path forward (tested on 7.0).

Fixes #129895

CC: `@japaric` `@flba-eb` `@saethlin`

Author: workingjubilee