When no suitable YACC is configured, supply useful informational messages
to users.  (Same way flex has been handled for a while.)

--- Postgres now accepts the example we claimed it wouldn't.  Miscellaneous
copy-editing as well.

weren't the master source.  We are now, and it really needs it.

Man, this brings back some old memories ...

so that ODBC driver doesn't go belly up by failing to recognize a
SELECT as such.

are now separate files "postgres.h" and "postgres_fe.h", which are meant
to be the primary include files for backend .c files and frontend .c files
respectively.  By default, only include files meant for frontend use are
installed into the installation include directory.  There is a new make
target 'make install-all-headers' that adds the whole content of the
src/include tree to the installed fileset, for use by people who want to
develop server-side code without keeping the complete source tree on hand.
Cleaned up a whole lot of crufty and inconsistent header inclusions.