pgsql: Change the sed rules in the regression test for pg_regress

Log Message:
-----------
Change the sed rules in the regression test for pg_regress hackery to create
the generated files, to help Visual C++ to run these tests.  The tests still
pass in VPATH and normal builds.

Patch from Magnus Hagander, editorialized by me.

Modified Files:
--------------
    pgsql/src/include:
        port.h (r1.108 -> r1.109)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/port.h.diff?r1=1.108&r2=1.109)
    pgsql/src/port:
        dirmod.c (r1.46 -> r1.47)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/port/dirmod.c.diff?r1=1.46&r2=1.47)
    pgsql/src/test/regress:
        GNUmakefile (r1.63 -> r1.64)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/GNUmakefile.diff?r1=1.63&r2=1.64)
        pg_regress.c (r1.25 -> r1.26)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/pg_regress.c.diff?r1=1.25&r2=1.26)