pgsql: Fix thinko introduced in 6b423ec67

Fix thinko introduced in 6b423ec67

As pointed out by Dean Rasheed, we really should be using tmp >
-(PG_INTNN_MIN / 10) rather than tmp > (PG_INTNN_MAX / 10) for checking
for overflows in the accumulation in the pg_strtointNN functions. This
does happen to be the same number when dividing by 10, but there is a
pending patch which adds other bases and this is not the same number if we
were to divide by 2 rather than 10, for example. If the base 2 parsing
was to follow this example then we could accidentally think a string
containing the value of PG_INT32_MIN was an overflow in pg_strtoint32.
Clearly that shouldn't overflow.

This does not fix any actual live bugs, only some bad examples of overflow
checks for future bases.

Reported-by: Dean Rasheed
Discussion: https://postgr.es/m/CAEZATCVEtwfhdm-K-etZYFB0=qsR0nT6qXta_W+GQx4RYph1dg@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/8692f6644e71f51db9a853a652f37909c9cb534d

Modified Files
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src/backend/utils/adt/numutils.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)