revdep_check() pausing for binary vs. source install

[kevinushey]

When running a revdepcheck for reticulate:

> revdepcheck::revdep_check(num_workers = 4)
── INIT ─────────────────────────────────────────────────── Computing revdeps ──
── INSTALL ─────────────────────────────────────────────────────── 2 versions ──
Installing CRAN version of reticulate
also installing the dependencies ‘jsonlite’, ‘rappdirs’, ‘Rcpp’

  There is a binary version available but the source version is later:
           binary source needs_compilation
reticulate   1.13   1.14              TRUE

Do you want to install from sources the package which needs compilation? (Yes/no/cancel)

I think in this case revdepcheck should always be installing from sources if the binary version is older.

[gaborcsardi]

That's often problematic is that system requirements are not available. Nevertheless you can make your own choice by setting the corresponding option or env var. See install.packages.compile.from.source in ?options.

[hadley]

I do think we should override the default value of "interactive" just so that you can start revdep checks without having to worry that they're interrupted by a prompt. I think this could be an argument to revdep_check().

[hadley]

Also check discussion in #233 to make sure that it succeeds either way.