sync: freebsd specific version

[felipensp]

Fix #19946

🤖[deprecated] Generated by Copilot at 5841084

Add sync_freebsd.v file to implement the sync module for FreeBSD. The file provides concurrency primitives using the C pthread and semaphore libraries. The change improves V's portability and compatibility on different operating systems.

🤖[deprecated] Generated by Copilot at 5841084

• Implement sync module for FreeBSD platform (link)

[spytheman]

That is a bit weird to me. I expected that the new platform file will be a copy of vlib/sync/sync_darwin.c.v, but apparently it worked with a copy of the default one 🤔, with just minimal changes.

[felipensp]

That is a bit weird to me. I expected that the new platform file will be a copy of vlib/sync/sync_darwin.c.v, but apparently it worked with a copy of the default one 🤔, with just minimal changes.

On Darwin implementation it does not use pointer in the typedef too (just like Linux).

[felipensp]

That is a bit weird to me. I expected that the new platform file will be a copy of vlib/sync/sync_darwin.c.v, but apparently it worked with a copy of the default one 🤔, with just minimal changes.

On this FreeBSD implementation, it does expects ** pointers to be provided to handle the allocation itself.

[spytheman]

I've tested the latest changes on my FreeBSD vps, and indeed works well. Excellent work.