Simplify make files, add full dependencies.

src/Makefile.global

src/backend/Makefile

src/backend/access/Makefile

src/backend/access/Makefile.inc

src/backend/access/common/Makefile

src/backend/access/common/Makefile.inc

src/backend/access/gist/Makefile

src/backend/access/gist/Makefile.inc

src/backend/access/hash/Makefile

src/backend/access/hash/Makefile.inc

src/backend/access/heap/Makefile

src/backend/access/heap/Makefile.inc

src/backend/access/index/Makefile

src/backend/access/index/Makefile.inc

src/backend/access/nbtree/Makefile

src/backend/access/nbtree/Makefile.inc

src/backend/access/rtree/Makefile

src/backend/access/transam/Makefile

src/backend/access/transam/Makefile.inc

src/backend/bootstrap/Makefile