Resolve "empty follow set assertion triggered with LALR"

Closes #92

See merge request !35

add TT_DOUBLE and TT_FLOAT as user-accessible token types

See merge request !32

Resolve "_POSIX_C_SOURCE breaks build on MacOS X"

Closes #93

See merge request !38

Resolve assertion failure with rules that can never match

Closes #83

See merge request !39

fixes issue #83

#83

doh! fixes issue 92 again.

tentative commit. this should solve issue 92, but isn't working, yet.

the idea is to taint any memoized follow set that hit a recursive loop,
directly or indirectly. the recursive calls (h_follow_rec) are allowed to use
these intermediates, but propagate the taint. the top-level routine (h_follow)
places the original taint on its result and may remove it at the end. it will
not return memoized results that are tainted (but compute them afresh).

without it, our test for issue 92 is no good (will always pass).
we could probably officially put it back if we simplify "dead"
symbols (that have no productions) out of the grammar beforehand.

there is a case where fs can be empty: when reducing by lhs would lead to
certain parse failure, by means of h_nothing_p() for instance.

fixes issue 83.

cf.
#83

this makes the computation more wasteful but avoids issue 92. intermediate
results could end up in the memoization table and be treated as final by
later calls to h_follow(). this problem could appear or not depending on the
order of nonterminals (i.e. pointers) in a hashtable.

hammer/hammer#92

hammer/hammer#87

Resolve "assertion failure with ambiguous LALR compiles"

Closes #91

See merge request hammer/hammer!34

Jni update

See merge request hammer/hammer!36

print arena stats only when running test_suite --verbose

See merge request hammer/hammer!33

development

update started from.

fixes issue 91