Wildcard usage enhancements in .pgpass

Hi,

Attached is the patch that improves usage of '*' wildcard in .pgpass,
particularly in the host part. The use case is below.

I work with multiple environments (like staging, production, performance
and so on), each one containing tens of different database clusters, each
cluster has its own subdomain in DNS, i.e. foo.test.db, bar.test.db and so
on. Each user has the same credentials on every database of a single
domain, i.e. .test.db databases, but different ones in other domains. For
those databases, each line in pgpass currently corresponds to a single
database, i.e.

foo1.test.db:5432:postgres:postgres:keep!tester
foo2.test.db:5432:postgres:postgres:keep!tsecret
...
foo99.test.db:5432:postgres:postgres:keep!tsecret
....
bar1.another.db.:5432:postgres:postgres:trustno1
bar2.another.db.:5432:postgres:postgres:trustno1
...

The problem I'm having is that there are just too many lines like those
(tens or even hundreds) and the new databases are added very frequently,
making it hard to keep .pgpass up-to-date.

What I'd like to have is an ability to specify a pattern in the hostname of
.pgpass, to replace the plenty of lines with one:

*.test.db:5432:postgres:postgres:keep!secret
bar*.*.db:5432:postgres:postgres:trustno1

The patch in attachment implements exactly this, by allowing '*' in the
hostname to substitute arbitrary number of characters until the dot. The
pattern is only matched when there is a '.' or ':' after the * and only in
the hostname, otherwise, '*' is treated like a normal character. It appears
that it can only be used for IPv4 addresses, i.e. instead of 255 hosts for
192.168.1.0/24 one can just specify 192.168.1.*.

I do understand that it might be a very limited use case in terms of
community plans for improving .pgpass, but I doubt that I'm the only one to
stumble upon the current limitation; the patch is quite small and might be
the first step into extending the functionality of .pgpass

It's currently missing the documentation, which I will add in case there
will be an interest in making this patch a part of the core.

Your feedback is greatly appreciated.

--
Regards,
Alexey Klyukin