* src/misc/accconv.cc (as_positive_product): Use a small loop instead
of calling bdd_satone().

* src/tgba/tgbaexplicit.hh (merge_transitions): Use a hash table
to merge compatible transitions.
* src/tgbatest/readsave.test: Add a test case.

* src/tgbaalgos/lbtt.cc: Renumber acceptance sets as they are read.
* src/tgbatest/lbttparse.test: Add a test cases.

* src/tgbaalgos/lbtt.cc: Do not expect a new line after the number of
acceptance conditions.
* src/tgbatest/lbttparse.test: Add a test case.

* src/ltlparse/ltlparse.yy (try_recursive_parse): Diagnose
empty strings.
* src/ltltest/lenient.test: Add tests.

Spin 6 supports formulas such as []<>(a < b) so that atomic properties
need not be specified using #define.  Of course we don't want to
implement all the syntax of Spin in our LTL parser because other tools
may have different syntaxes for their atomic propositions.  The
lenient mode tells the scanner to return any (...), {...}, or {...}!
block as a single token.  The parser will try to recursively parse
this block as a LTL/SERE formula, and if this fails, it will consider
the block to be an atomic proposition.  The drawback is that most
syntax errors will no be considered to be atomic propositions.  For
instance (a U b U) is a single atomic proposition in lenient mode, and
a syntax error in default mode.

* src/ltlparse/ltlparse.yy, src/ltlparse/ltlscan.ll,
src/ltlparse/parsedecl.hh, src/ltlparse/public.hh: Add a
lenient parsing mode.  Simplify the lexer using yy_scan_string.
* src/bin/common_finput.cc: Add a --lenient option.
* src/ltltest/lenient.test: New file.
* src/ltltest/Makefile.am: Add it.
* src/neverparse/neverclaimparse.yy: Parse the guards in lenient mode.
* src/tgbatest/neverclaimread.test: Adjust.
* src/ltlvisit/tostring.cc: When outputing a formula in Spin's syntax,
output (a < b) instead of "a < b".
* src/misc/escape.cc, src/misc/escape.hh (trim): New helper function.

* src/bin/ltl2tgba.cc, src/bin/ltl2tgta.cc: Destroy the translated
formulas.
* src/bin/ltlcheck.cc, src/bin/ltlfilt.cc: Free the unicity table on
exit.

* src/bin/ltlcheck.cc: filter duplicate formulas, unless the
new --allow-dups option is used.

* src/bin/man/genltl.x, src/bin/man/ltlcheck.x, src/bin/man/ltlfilt.x,
src/bin/man/randltl.x: Use .BR in the SEE ALSO section.

* src/bin/ltlcheck.cc: Add option --json and --csv.
* src/bin/man/ltlcheck.x: Adjust examples.
* src/tgbatest/ltlcheck.test: Do not output any statistic.
* src/tgbatest/ltlcheck2.test: Output both JSON and CSV stats.

* src/bin/ltlcheck.cc: Here.

* src/tgbatest/ltlcheck.test, src/tgbatest/ltlcheck2.test: New files.
* src/tgbatest/Makefile.am: Add them.

* src/bin/ltlcheck.cc (sig_handler): Exit when receiving the signal.

* src/bin/man/ltlcheck.x: New file.
* src/bin/man/Makefile.am: Add it.
* src/bin/ltlcheck.cc: Arrange help text.

* src/ltlast/formula.hh (has_lbt_atomic_props): New method.
* src/ltlast/formula.cc (printprops): Display it.
* src/ltlast/atomic_prop.cc: Update it.
* src/bin/ltlcheck.cc, src/bin/genltl.cc: Use it.
* doc/tl/tl.tex: Menton has_lbt_atomic_props().

* configure.ac: Check for kill and alarm.
* src/bin/ltlcheck.cc: Disable timeout code when kill or alarm are
missing.  Recognize the --timeout option, but display a warning.

kill(-x,y) is more portable than killpg(x,y)

* src/bin/ltlcheck.cc: Use kill.

Also, upgrade to gnulib 4af1990a0902f5914f582bade9d1aa843a291f5a.

* lib/sys_wait.in.h, m4/sys_wait_h.m4: New files.
* m4/sys_stat_h.m4, m4/stdlib_h.m4, m4/gnulib-comp.m4,
m4/gnulib-cache.m4, lib/stdlib.in.h, lib/Makefile.am: Update.

* src/tgbaalgos/lbtt.cc (lbtt_read_gba): New function.
(lbtt_parse): Call lbtt_read_gba.
* src/tgbatest/lbttparse.test: Add a test.

We used to output 0 and 1, but "spin -f" does not under understand
that.

* src/ltlvisit/tostring.cc (kw_spin): Output true and false instead of
0 and 1.

* src/bin/ltlcheck.cc: Add option -T and machinery for signal handling.

* lib/gethrxtime.h, lib/xtime.h: Add extern "C".
* src/bin/Makefile.am (ltlcheck_LDADD): Use LIB_GETHRXTIME.
* src/bin/ltlcheck.cc: Use gethrxtime() to record translation time.

gnulib 9e117ae955a5c6a0406140e62b76c3ef50e3bc2b.

* lib/gethrxtime.c, lib/gethrxtime.h, lib/gettime.c, lib/timespec.c,
lib/timespec.h, lib/xtime.h, m4/clock_time.m4, m4/gethrxtime.m4,
m4/gettime.m4, m4/timespec.m4: New files.
* m4/gnulib-cache.m4, m4/gnulib-comp.m4, lib/Makefile.am: Adjust.

* src/bin/ltlcheck.cc (translator_runner::formula): New function.
(processor::process_formula): Use it.

* src/misc/formater.hh (formater::format, formater::prime): Move ...
* src/misc/formater.cc: ... in this new file.
* src/misc/Makefile.am: Add it.
* src/sanity/style.test: Allow <iostream> in headers where << or >> are
used.

* src/misc/formater.hh (printable_value): Add more accessors.
* src/bin/ltlcheck.cc: Use the formater class to factor the %-expansion
loop, and reuse filenames (such as %F, %S, and %L) between executions
on the same formula.

* src/misc/formater.hh: New file.
* src/misc/Makefile.am: Add it.
* src/tgbaalgos/stats.cc, src/tgbaalgos/stats.hh: Use it.