Partial revamp of `scripts/crosscompile`

Fix #430.
Added regex support as per issue #164.

jq now depends on oniguruma for regex support.
Modified configure.ac accordingly.

Added valgrind suppression file for oniguruma to prevent one-time and bounded
leaks from causing tests to fail.

Signed-off-by: Nicolas Williams <nico@cryptonector.com>
Remove extra free of testmode

I added a jv_free() too many while rebasing @wtlangford's contribution.
It could only be triggered by calling `_match_impl` directly.
Allow stacking of short options (fix #346)
Remove stray fprintf() from last commit
Fix option stacking bug
Tail call optimization (close #437)
Improve TCO

Instead of checking for self-recursion check that the thing we're
calling is a function and not a closure, therefore the new frame will
have the same env as the current frame.
Get "Try Online" button working (fix #440)