pgsql: Adjust configure's handling of libedit to not look for a

Log Message:
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Adjust configure's handling of libedit to not look for a history.h file.
Per Bob Friesenhahn's report, this file is not supplied by some versions
of libedit, and even when it is supplied it seems to be just a link to
readline.h, so we don't need to include it anyway.
Also, ensure that we won't try to use a too-old version of Bison.
The previous coding would bleat but then use it anyway; better to invoke
the 'missing' script if any grammar files need to be rebuilt.

Modified Files:
--------------
pgsql:
configure (r1.509 -> r1.510)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/configure.diff?r1=1.509&r2=1.510)
configure.in (r1.479 -> r1.480)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/configure.in.diff?r1=1.479&r2=1.480)
pgsql/src/include:
pg_config.h.in (r1.102 -> r1.103)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/pg_config.h.in.diff?r1=1.102&r2=1.103)