pgsql: Fix warnings in cpluspluscheck

Fix warnings in cpluspluscheck

Various int variables were compared to macros that are of type size_t,
which caused -Wsign-compare warnings in cpluspluscheck.  Change those
to size_t, which also better describes their purpose.

Per report from Peter Eisentraut

Discussion: https://postgr.es/m/486847dc-6de5-464a-938e-bac98ec2438b%40eisentraut.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/25799850867292efecf34da73db4ea1ad1aad573

Modified Files
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src/include/common/hashfn_unstable.h | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)