Show C source in HL output

[nspitko]

I often find myself wanting to see how hl/c deals with certain things (inlining, allocations, abstracts, etc).

JS already has this, adding it to HL would be neat too. Possibly as an additional toggle in the settings page since this will require a second compilation.

[barisyild]

try.haxe.org does not support hl/c.