build: allow passing multiple libs to pkg_config

Sometimes it's necessary to pass multiple library names to pkg-config,
e.g. the brotli shared libraries can be pulled in with
    pkg-config libbrotlienc libbrotlidec

Update the code to handle both, strings (as used so far), and lists
of strings.

Signed-off-by: André Draszik <git@andred.net>

PR-URL: https://github.com/nodejs/node/pull/32046


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>