pgsql: Fix unportable usage of functions.

Fix unportable usage of <ctype.h> functions.

isdigit(), isspace(), etc are likely to give surprising results if passed a
signed char.  We should always cast the argument to unsigned char to avoid
that.  Error in commit d78a7d9c7fa3e9cd, found by buildfarm member gaur.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/cb0ca0c9953aa0614e7b143bd2440a7582a27233

Modified Files
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src/backend/tsearch/spell.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)