pgsql: Extract tarballs with "o" option (tar xof), to behave reasonably

Log Message:
-----------
Extract tarballs with "o" option (tar xof), to behave reasonably when run
as root, as would usually be the case during make install.

per bug #4883

Modified Files:
--------------
pgsql/doc:
Makefile (r1.35 -> r1.36)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/Makefile?r1=1.35&r2=1.36)