clang: Fix -gz=zlib options for linker

Clang commit ccb4124a4172bf2cb2e1cd7c253f0f1654fce294:

Fix -gz=zlib options for linker

gcc translates -gz=zlib to --compress-debug-options=zlib for both
assembler and linker but clang only does this for assembler.

The linker needs --compress-debug-options=zlib option to compress the
debug sections in the generated executable or shared library.

Due to this bug, -gz=zlib has no effect on the generated executable or
shared library.

This patch fixes that.

Clang commit 462cf39a5c180621b56f7602270ce33eb7b68d23:

[Driver] Fix -gz=zlib options for linker also on FreeBSD

ccb4124a4172 fixed translating -gz=zlib to --compress-debug-sections for
linker invocation for several ToolChains, but omitted FreeBSD.

Approved by: dim
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D29028