toolchain: handle toolchains with multiple ld*.so.* files

Some 3rd party vendor toolchains have multiple files which match
these glob patterns.  In this case, the shell script failed.
Switching to use find and xargs solves the issue.

Signed-off-by: Jonah Petri <jonah@petri.us>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>