pgsql: Commonalize process startup code.

Commonalize process startup code.

Move common code, that was duplicated in every postmaster child/every
standalone process, into two functions in miscinit.c.  Not only does
that already result in a fair amount of net code reduction but it also
makes it much easier to remove more duplication in the future. The
prime motivation wasn't code deduplication though, but easier addition
of new common code.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/31c453165b5a656044ce1dbce89f5828c1c7e23c

Modified Files
--------------
src/backend/bootstrap/bootstrap.c     |   26 ++-----------
src/backend/postmaster/autovacuum.c   |   49 ++----------------------
src/backend/postmaster/bgworker.c     |   18 ---------
src/backend/postmaster/bgwriter.c     |   12 ------
src/backend/postmaster/checkpointer.c |   11 ------
src/backend/postmaster/pgarch.c       |   20 +---------
src/backend/postmaster/pgstat.c       |   22 +----------
src/backend/postmaster/postmaster.c   |   60 +++++-------------------------
src/backend/postmaster/startup.c      |    9 -----
src/backend/postmaster/syslogger.c    |   22 ++---------
src/backend/postmaster/walwriter.c    |   13 -------
src/backend/replication/walreceiver.c |   11 ------
src/backend/tcop/postgres.c           |   28 +-------------
src/backend/utils/init/miscinit.c     |   66 +++++++++++++++++++++++++++++++++
src/include/miscadmin.h               |    3 ++
15 files changed, 96 insertions(+), 274 deletions(-)