pgsql-server: Allow plpgsql to pass composite-type arguments (ie,

Log Message:
-----------
Allow plpgsql to pass composite-type arguments (ie, whole-row variables)
into SQL expressions.  At present this only works usefully for variables
of named rowtypes, not RECORD variables, since the SQL parser can't infer
anything about datatypes from a RECORD Param.  Still, it's a step forward.

Modified Files:
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    pgsql-server/src/pl/plpgsql/src:
        gram.y (r1.54 -> r1.55)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/pl/plpgsql/src/gram.y.diff?r1=1.54&r2=1.55)
        pl_exec.c (r1.102 -> r1.103)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/pl/plpgsql/src/pl_exec.c.diff?r1=1.102&r2=1.103)