Fix #16937; --clib option pass library name to backend C compiler correctly

[demotomohiro]

No description provided.

[Varriount]

Can you give a description of what the previous behavior was, why it was incorrect, and what the new behavior is?

[demotomohiro]

Previous behavior convert a --clib parameter to full path and pass it to backend C compiler.
It doesn't work when you want to link C libraries in system library directories.

For example:

$ nim c --clib:my_c_lib --listcmd test.nim

Hint: gcc   -o /tmp/tmphjk/testnim/test  /tmp/nimcache/d/test/stdlib_digitsutils.nim.c.o /tmp/nimcache/d/test/stdlib_dollars.nim.c.o /tmp/ni
mcache/d/test/stdlib_io.nim.c.o /tmp/nimcache/d/test/stdlib_system.nim.c.o /tmp/nimcache/d/test/@mtest.nim.c.o    -l/tmp/tmphjk/testnim/my_c
_lib -ldl [Link]

In this example, my_c_lib was convert to /tmp/tmphjk/testnim/my_c_lib.

This PR doesn't convert --clib parameter to full path before passing it to backend C compiler.
So nim c --clib:my_c_lib --listcmd test.nim passes -lmy_c_lib to backend C compiler at link time.

[github-actions]

Thanks for your hard work on this PR!
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