DESTDIR removed, again.

src/backend/Makefile

src/bin/cleardbdir/Makefile

src/bin/createdb/Makefile

src/bin/createuser/Makefile

src/bin/destroydb/Makefile

src/bin/destroyuser/Makefile

src/bin/initdb/Makefile

src/bin/initlocation/Makefile

src/bin/ipcclean/Makefile

src/bin/pg_dump/Makefile.in

src/bin/pg_id/Makefile

src/bin/pg_passwd/Makefile

src/bin/pg_version/Makefile.in

src/bin/pgtclsh/Makefile

src/bin/psql/Makefile.in

src/interfaces/ecpg/include/Makefile

src/interfaces/ecpg/lib/Makefile.in

src/interfaces/ecpg/preproc/Makefile

src/interfaces/libpgtcl/Makefile.in

src/interfaces/libpq++/Makefile