- ### Problem

  Since https://github.com/ruby/rubygems/pull/9131, we are now
  compiling make rules simultaneously. The number of jobs
  is equal to the number of processors.
  This may be problematic for some users as they want to control
  this value.

  ### Solution

  The number of jobs passed to `make` will now be equal to the
  `BUNDLE_JOBS` value.

  ### Side note

  It's also worth to note that since Bundler installs gems in
  parallel, we may end up running multiple `make -j<JOB>` in parallel
  which would cause exhaust the number of processors we have.
  This problem can be fixed by implementing a GNU jobserver, which I
  plan to do. But I felt that this would be too much change in one PR.

https://github.com/ruby/rubygems/commit/d51995deb9

The previous regex didn't properly match quoted strings
it would capture the opening quote as part of the version
if quotes were mismatched.
This change properly parses double-quoted, single-quoted,
and unquoted version strings separately.

https://github.com/ruby/rubygems/commit/81e48c8185

https://github.com/ruby/rubygems/commit/a7d7ab39dd

https://github.com/ruby/rubygems/commit/a091e3fd10

- Fix https://github.com/ruby/rubygems/pull/9188
- This message is a bit misleading because it always outputs one extra
  specs, which is Bundler itself.

  This is now fixed when the message is about to be output.

https://github.com/ruby/rubygems/commit/70b4e19506