* src/gram.h (rule_t): `guard' and `guard_line' are new members.

* src/gram.h (rule_t): `guard' and `guard_line' are new members.
* src/reader.c (symbol_list): `guard' and `guard_line' are new
members.
(symbol_list_new): Adjust.
(copy_action): action_line is the first line, not the last.
(copy_guard): Just as for actions, store the `action' only, not
the switch/case/break flesh.
Don't parse the user action that might follow the guard, let...
(readgram): do it, i.e., now, there can be an action after a
guard.
In other words the guard is just explicitly optional.
(packgram): Adjust.
* src/output.c (guards_output): New.
(output_parser): Call it when needed.
(output): Also free the guard and attrs obstacks.
* src/files.c, src/files.h (obstack_save): Remove.
(output_files): Remove.
As a result, if one needs the former `.act' file, using an
appropriate skeleton which requires actions and guards is now
required.
* src/main.c (main): Adjust.
* tests/semantic.at: New.
* tests/regression.at: Use `input.y' as input file name.
Avoid 8+3 problems by requiring input.c when the test needs the
parser.