Earlier we propagated all free args specified for a compilation into
a link task. It was required because the link task actually compiled
the same source as the compile task but with another output kind.
But currently a link task produces a final binary from a klib instead
of sources. It means that such a propagation becomes incorrect. Now
options related to the compiler frontend like -Xexperimental must
be specified per compilation while options related to the compiler
backend (e.g. -opt, -g, -Xstatic-framework etc) - per binary.
This path shows a special warning if some of "binary-specific"
arguments are passed to a compilation.
Ilya Matveev
f07e0594e2