pgsql: Move psql's psqlscan.l into src/fe_utils.

Move psql's psqlscan.l into src/fe_utils.

This completes (at least for now) the project of getting rid of ad-hoc
linkages among the src/bin/ subdirectories. Everything they share is now
in src/fe_utils/ and is included from a static library at link time.

A side benefit is that we can restore the FLEX_NO_BACKUP check for
psqlscanslash.l. We might need to think of another way to do that check
if we ever need to build two lexers with that property in the same source
directory, but there's no foreseeable reason to need that.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/c1156411ad0879a71956b64aa487babe7572685b

Modified Files
--------------
src/backend/parser/scan.l | 2 +-
src/bin/pgbench/Makefile | 17 +-
src/bin/pgbench/exprscan.l | 2 +-
src/bin/pgbench/pgbench.h | 2 +-
src/bin/psql/.gitignore | 1 -
src/bin/psql/Makefile | 15 +-
src/bin/psql/command.h | 2 +-
src/bin/psql/mainloop.c | 1 +
src/bin/psql/mainloop.h | 2 +-
src/bin/psql/nls.mk | 4 +-
src/bin/psql/prompt.h | 13 +-
src/bin/psql/psqlscan.h | 62 --
src/bin/psql/psqlscan.l | 1424 ----------------------------------
src/bin/psql/psqlscan_int.h | 129 ----
src/bin/psql/psqlscanslash.h | 2 +-
src/bin/psql/psqlscanslash.l | 4 +-
src/fe_utils/.gitignore | 1 +
src/fe_utils/Makefile | 27 +-
src/fe_utils/psqlscan.l | 1428 +++++++++++++++++++++++++++++++++++
src/include/fe_utils/psqlscan.h | 85 +++
src/include/fe_utils/psqlscan_int.h | 144 ++++
src/tools/msvc/Mkvcbuild.pm | 17 +-
src/tools/msvc/clean.bat | 2 +-
23 files changed, 1708 insertions(+), 1678 deletions(-)