[generate-swc.sh] Use array instead of string for arguments

I was actually getting an error when using a library folder due to a
misunderstanding of how shell handles strings.

See the following page for an explanation:
http://mywiki.wooledge.org/BashFAQ/050#I.27m_constructing_a_command_based_on_information_that_is_only_known_at_run_time