pgsql: Move pqsignal() to libpgport.

Move pqsignal() to libpgport.

We had two copies of this function in the backend and libpq, which was
already pretty bogus, but it turns out that we need it in some other
programs that don't use libpq (such as pg_test_fsync). So put it where
it probably should have been all along. The signal-mask-initialization
support in src/backend/libpq/pqsignal.c stays where it is, though, since
we only need that in the backend.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/da5aeccf64b37a8e9bd3cb605848590595dbcbf8

Modified Files
--------------
contrib/pgbench/pgbench.c | 1 -
src/backend/access/transam/xlog.c | 1 -
src/backend/libpq/pqsignal.c | 67 +---------------------------
src/backend/main/main.c | 3 -
src/backend/port/win32/signal.c | 8 +++-
src/backend/port/win32/timer.c | 2 -
src/backend/replication/walsender.c | 1 -
src/backend/utils/misc/timeout.c | 1 -
src/bin/initdb/.gitignore | 1 -
src/bin/initdb/Makefile | 9 +---
src/bin/initdb/initdb.c | 1 -
src/bin/pg_basebackup/pg_receivexlog.c | 1 -
src/bin/pg_ctl/pg_ctl.c | 1 -
src/bin/psql/common.c | 2 -
src/bin/psql/copy.c | 1 -
src/bin/psql/print.c | 1 -
src/bin/scripts/common.c | 1 -
src/include/libpq/pqsignal.h | 11 +----
src/include/port.h | 7 +++
src/interfaces/libpq/Makefile | 2 +-
src/interfaces/libpq/bcc32.mak | 2 -
src/interfaces/libpq/fe-misc.c | 1 -
src/interfaces/libpq/fe-print.c | 1 -
src/interfaces/libpq/fe-secure.c | 1 -
src/interfaces/libpq/pqsignal.c | 49 --------------------
src/interfaces/libpq/pqsignal.h | 25 ----------
src/interfaces/libpq/win32.mak | 2 -
src/pl/plperl/plperl.c | 1 -
src/port/Makefile | 3 +-
src/port/pqsignal.c | 76 ++++++++++++++++++++++++++++++++
30 files changed, 99 insertions(+), 184 deletions(-)