There, now we support GiST...now what? :)

src/backend/access/Makefile.inc

src/backend/access/genam.h

src/backend/access/hash.h

src/backend/access/hash/hash.c

src/backend/access/index/indexam.c

src/backend/access/nbtree.h

src/backend/access/nbtree/nbtree.c

src/backend/access/rtree/rtree.c

src/backend/catalog/index.c

src/backend/catalog/index.h

src/backend/catalog/indexing.c

src/backend/catalog/pg_am.h

src/backend/catalog/pg_index.h

src/backend/catalog/pg_proc.h

src/backend/commands/cluster.c

src/backend/commands/copy.c

src/backend/commands/defind.c

src/backend/executor/execUtils.c

src/backend/nodes/equalfuncs.c

src/backend/nodes/parsenodes.h