Log Message:
(devel/R-pkgbuild) Updated 1.3.1 to 1.4.0

# pkgbuild 1.4.0

* pkgbuild can now avoid copying large package directories when building a
  source package. See the `PKG_BUILD_COPY_METHOD` enviroment variable in
  `?build` or the package README (#59).

  This is currently an experimental feature, and feedback is
  appreciated.

* `R CMD build` warnings can now be turned into errors, by setting the
  `pkg.build_stop_for_warnings` option to `TRUE` or by setting the
  `PKG_BUILD_STOP_FOR_WARNINGS` environment variable to `true` (#114).

* `need_compile()` now knows about Rust source code files, i.e. `Cargo.toml`
  and `*.rs` (#115).

* Now `pkgbuild::build()` will not clean up `inst/doc` by default if the
  `Config/build/clean-inst-doc` entry in `DESCRIPTION` is set to `FALSE` (#128).

* New `PKG_BUILD_COLOR_DIAGNOSTICS` environment variable to opt out from
  colored compiler output (#141).

* pkgbuild now works with a full XCode installation if the XCode Command
  Line Tools are not installed, on macOS, in RStudio (#103).