Re: Add --include-table-data-where option to pg_dump, to export onlya subset of table data

Most notably, the command-line option is shortened to simply --where, which is much easier to read and understand,

and matches the earlier proposal [1].

 bool
-simple_oid_list_member(SimpleOidList *list, Oid val)
+simple_oid_list_member2(SimpleOidList *list, Oid val, void **extra_data)

I feel like that isn't in the spirit of Lisp "member".  It's now a
kind of association list.

My new patch has this function named simple_oid_list_find_data, to indicate that it's working with some extra data,

and the corresponding append is called simple_oid_list_append_data.

This is now addressed in the v4 patch.  I've added a new function to string_utils,

called findUnquotedChar, which is used to find the colon character in the command-line argument,

which separates the table name from the filter clause.

For example, if you have a table called "foo:bar", then you would use the --where option as follows:

  pg_dump --where '"foo:bar":created_at >= '2018-05-01'" dbname

If you have a table with a double-quote in the name (gah!), as well as colons, like:  has"quote:and:colons

then this still works, because such quotes in the name are escaped by doubling the quote char,

e.g. "has""quote:and:colons", and also works with this patch:

  pg_dump --where '"has""quote:and:colons":created_at >= '2018-05-1'" dbname