[build2] bpkg: curl fails without retry

[Boris Kolpackov]

Feiyun Wang <feiyunw at yahoo.com> writes:

> I suggest that bpkg-stage can retry for some times automatically when
> curl fails, like wget does.

Automatically retrying means adding another option (to configure the
number of retries or to disable them) and dragging it through all the
levels of build and bootstrap scripts. This both increases complexity,
number of logic paths to test, etc. At the same time, it is fairly
simple to just restart the build/bootstrap script from scratch.

But if you really need retries, feel free to customize the relevant
scripts yourself (you can pass the necessary curl options to bpkg via
--fetch-option).