pgsql: Define the FRONTEND symbol in postgres_fe.h, which allows us to

Log Message:
-----------
Define the FRONTEND symbol in postgres_fe.h, which allows us to eliminate
duplicative -DFRONTEND flags from many Makefiles.  We still need Makefile
control of the symbol in a few places that compile frontend-or-backend
src/port/ files, but it's a lot cleaner than before.

Hiroshi Saito

Modified Files:
--------------
    pgsql/src/bin/initdb:
        Makefile (r1.52 -> r1.53)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/initdb/Makefile?r1=1.52&r2=1.53)
    pgsql/src/bin/pg_config:
        Makefile (r1.18 -> r1.19)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_config/Makefile?r1=1.18&r2=1.19)
    pgsql/src/bin/pg_controldata:
        Makefile (r1.15 -> r1.16)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_controldata/Makefile?r1=1.15&r2=1.16)
    pgsql/src/bin/pg_ctl:
        Makefile (r1.23 -> r1.24)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_ctl/Makefile?r1=1.23&r2=1.24)
    pgsql/src/bin/pg_dump:
        Makefile (r1.63 -> r1.64)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/Makefile?r1=1.63&r2=1.64)
    pgsql/src/bin/pg_resetxlog:
        Makefile (r1.17 -> r1.18)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_resetxlog/Makefile?r1=1.17&r2=1.18)
    pgsql/src/bin/psql:
        Makefile (r1.58 -> r1.59)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/Makefile?r1=1.58&r2=1.59)
    pgsql/src/bin/scripts:
        Makefile (r1.37 -> r1.38)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/scripts/Makefile?r1=1.37&r2=1.38)
    pgsql/src/include:
        postgres_fe.h (r1.12 -> r1.13)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/postgres_fe.h?r1=1.12&r2=1.13)
    pgsql/src/interfaces/ecpg/ecpglib:
        Makefile (r1.47 -> r1.48)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/ecpglib/Makefile?r1=1.47&r2=1.48)
    pgsql/src/interfaces/ecpg/include:
        Makefile (r1.30 -> r1.31)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/include/Makefile?r1=1.30&r2=1.31)
    pgsql/src/interfaces/ecpg/pgtypeslib:
        Makefile (r1.32 -> r1.33)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/pgtypeslib/Makefile?r1=1.32&r2=1.33)
    pgsql/src/tools/findoidjoins:
        Makefile (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/findoidjoins/Makefile?r1=1.3&r2=1.4)
    pgsql/src/tools/fsync:
        Makefile (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/fsync/Makefile?r1=1.4&r2=1.5)
    pgsql/src/tools/msvc:
        Mkvcbuild.pm (r1.16 -> r1.17)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/Mkvcbuild.pm?r1=1.16&r2=1.17)