pgsql: Improve ispell dictionary's defenses against bad affix files.

Improve ispell dictionary's defenses against bad affix files.

Don't crash if an ispell dictionary definition contains flags but not
any compound affixes. (This isn't a security issue since only superusers
can install affix files, but still it's a bad thing.)

Also, be more careful about detecting whether an affix-file FLAG command
is old-format (ispell) or new-format (myspell/hunspell). And change the
error message about mixed old-format and new-format commands into something
intelligible.

Per bug #11770 from Emre Hasegeli. Back-patch to all supported branches.

Branch
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REL9_3_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/385f0d98a4357f144e7ed9b18db7ead9079b9318

Modified Files
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src/backend/tsearch/spell.c | 70 +++++++++++++++++++++++++++----------------
1 file changed, 44 insertions(+), 26 deletions(-)