pgsql: Refine win32env.c cosmetics.

Refine win32env.c cosmetics.

Replace use of plain 0 as a null pointer constant.  In comments, update
terminology and lessen redundancy.  Back-patch to 9.2 (all supported
versions) for the convenience of back-patching the next two commits.

Christian Ullrich and Noah Misch, reviewed (in earlier versions) by
Michael Paquier.

Branch
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REL9_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/117818252d96cb6cb99c72da936d3371680c3768

Modified Files
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src/port/win32env.c | 46 +++++++++++++++++++---------------------------
1 file changed, 19 insertions(+), 27 deletions(-)