Build System Downloads Files at the Configuration Stage

[herrhotzenplotz]

Unfortunately when I was updating my FreeBSD Ports overlay for contour and pushed it through the automatic package builder poudriere I got build failures due to CMake downloading files (the UCD zip) at configuration time where network access is completely disabled.

I believe I pointed this out before in tickets in contour.

My suggestion would be to either:

• Vendor the UCD files or ship them in the distribution tarball or
• Let the build system check for the files' existence and error out if they are missing. Additionally provide a script to download them for the user. This way package/port maintainers can add them to the distfile list.

Related to #42

[christianparpart]

Hey. Oh damn. Thanks. There is a way to prefetch the dist files, just like done for contour embedded deps. Let me reply in detail tomorrow (sadly occupied currently).