Add --cache option to ruby_deploy to cache .rbo files

[MSch]

Hi,

in ruby_deploy the mtime comparison always fails since Xcode copies the file to the build dir without preserving mtime.

I've written a per-default disabled --cache command line switch that caches the compiled .rbo files (+ SHA1 of the source file) in .rbo-cache, which speeds up ruby_deploy by a huge amount for big projects

If run with --cache ruby_deploy will mirror the directory structure of Contents/Resources in .rbo-cache and save the compiled rbos and the SHA1 of the source files there on a per ARCH basis. The next time ruby_deploy --cache gets invoked it checks to see which rbos it can just copy and which have to be compiled (and then cached)
The mtime checking is kept too.

Currently there's no cache pruning, you just have to remove .rbo-cache from time to time if you add/delete many files, but that can be added.

[lrz]

Interesting change. Would it is possible to make this automatic? (and perhaps introduce a --no-cache option to avoid caching).

This way, existing projects will build faster without the need to change their Xcode project files.

[ferrous26]

Seems this pull request is dead. It also will not merge cleanly.

I'd rather not throw this away, so if there are no objections, I'll try and get it cleaned up (including turning it on by default) soon.