pgsql: Remove IRIX port.

Remove IRIX port.

Development of IRIX has been discontinued, and support is scheduled
to end in December of 2013.  Therefore, there will be no supported
versions of this operating system by the time PostgreSQL 9.4 is
released.  Furthermore, we have no maintainer for this platform.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/ea91a6be89575095f61ebf36d67c2df98be093db

Modified Files
--------------
configure                         |    2 --
configure.in                      |    2 --
doc/src/sgml/dfunc.sgml           |   16 ----------
doc/src/sgml/installation.sgml    |   62 ++---------------------------------
src/Makefile.shlib                |   10 ------
src/backend/port/dynloader/irix.c |    6 ----
src/backend/port/dynloader/irix.h |   46 --------------------------
src/backend/utils/adt/float.c     |   64 -------------------------------------
src/include/port/irix.h           |    7 ----
src/include/storage/s_lock.h      |   25 ---------------
10 files changed, 3 insertions(+), 237 deletions(-)