make distclean keeps some files

Playing with diffs, I've noticed, that after `make distclean` command some
files are still present in the source tree. They're were not there before
./configure && make.

They are:
src/backend/bootstrap/bootparse.c
src/backend/bootstrap/bootscanner.c
src/backend/bootstrap/bootstrap_tokens.h
src/backend/parser/gram.c
src/backend/parser/parse.h
src/backend/parser/scan.c
src/backend/utils/misc/guc-file.c
src/bin/psql/psqlscan.c
src/bin/psql/sql_help.h
src/interfaces/ecpg/preproc/pgc.c
src/interfaces/ecpg/preproc/preproc.c
src/interfaces/ecpg/preproc/preproc.h
src/interfaces/libpq/blibpqdll.def
src/interfaces/libpq/libpqddll.def
src/interfaces/libpq/libpqdll.def
src/interfaces/libpq/libpq.rc
src/pl/plpgsql/src/pl_gram.c
src/pl/plpgsql/src/pl_scan.c
src/pl/plpgsql/src/pl.tab.h

Are they kept intentionally?

--

Victor Y. Yegorov