syscall: replace panic with error return in Accept4 on FreeBSD

[feizaizheli]

The Accept4 function on FreeBSD uses panic when the returned address length exceeds SizeofSockaddrAny. This is inconsistent with Go's error handling philosophy and can crash the entire program.

This commit replaces the panic with proper error handling: closing the accepted file descriptor and returning EINVAL error, which allows callers to handle the exceptional case gracefully.

Changes:

• Close the newly accepted fd before returning error
• Return EINVAL instead of panicking
• Maintain consistency with other error handling in the same function

If this approach is acceptable, similar changes can be applied to other platforms (NetBSD, OpenBSD, DragonflyBSD, Linux, Solaris).

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Message from Gopher Robot:

Patch Set 1:

(1 comment)

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