pgsql-server: Put path configuration information into a .h file instead

Log Message:
-----------
Put path configuration information into a .h file instead of cluttering
several different module Makefiles with it.  Also, do any adjustment
of installation paths during configure, rather than every time Makefile.global
is read.

Modified Files:
--------------
    pgsql-server:
        configure (r1.367 -> r1.368)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/configure.diff?r1=1.367&r2=1.368)
        configure.in (r1.356 -> r1.357)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/configure.in.diff?r1=1.356&r2=1.357)
    pgsql-server/src:
        Makefile.global.in (r1.185 -> r1.186)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/Makefile.global.in.diff?r1=1.185&r2=1.186)
    pgsql-server/src/backend/utils/fmgr:
        Makefile (r1.16 -> r1.17)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/utils/fmgr/Makefile.diff?r1=1.16&r2=1.17)
    pgsql-server/src/interfaces/libpq:
        Makefile (r1.107 -> r1.108)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/interfaces/libpq/Makefile.diff?r1=1.107&r2=1.108)
        fe-connect.c (r1.269 -> r1.270)

(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/interfaces/libpq/fe-connect.c.diff?r1=1.269&r2=1.270)
    pgsql-server/src/port:
        Makefile (r1.11 -> r1.12)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/port/Makefile.diff?r1=1.11&r2=1.12)
        path.c (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/port/path.c.diff?r1=1.10&r2=1.11)