pgsql: Be pickier about converting between Name and Datum.

Be pickier about converting between Name and Datum.

We were misapplying NameGetDatum() to plain C strings in some places.
This worked, because it was just a pointer cast anyway, but it's a type
cheat in some sense.  Use CStringGetDatum instead, and modify the
NameGetDatum macro so it won't compile if applied to something that's
not a pointer to NameData.  This should result in no changes to
generated code, but it is logically cleaner.

Mark Dilger, tweaked a bit by me

Discussion: <EFD8AC94-4C1F-40C1-A5EA-304080089C1B@gmail.com>

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/55c3391d1e6a201b5b891781d21fe682a8c64fe6

Modified Files
--------------
src/backend/commands/dbcommands.c | 8 ++++----
src/backend/commands/proclang.c   | 2 +-
src/backend/commands/typecmds.c   | 2 +-
src/include/postgres.h            | 2 +-
4 files changed, 7 insertions(+), 7 deletions(-)