pgsql: Rename the C functions bitand(), bitor() to bit_and(), bit_or().

Rename the C functions bitand(), bitor() to bit_and(), bit_or().

This is to avoid use of the C++ keywords "bitand" and "bitor" in
the header file utils/varbit.h. Note the functions' SQL-level
names are not changed, only their C-level names.

In passing, make some comments in varbit.c conform to project-standard
layout.

Branch
------
master

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=84fc571395f6986d912cda6c09826cb10caee7f0

Modified Files
--------------
src/backend/utils/adt/varbit.c | 60 +++++++++++++++++++++++++------------
src/include/catalog/catversion.h | 2 +-
src/include/catalog/pg_proc.h | 4 +-
src/include/utils/varbit.h | 5 ++-
4 files changed, 46 insertions(+), 25 deletions(-)