Handle additional edge cases in puppet.gemspec

Previously, running `gem build puppet.gemspec` on windows included the
windows-specific runtime dependencies in the "ruby" puppet-<version>.gem,
because of the `Gem.win_platform?` condition.

Now add the runtime dependencies if we're running on that platform via bundler.
or if we're building a gem for that platform. In the latter case, it doesn't
matter which platform we're running on.

This also relaxes the darwin and mingw platforms, to future proof against other
variations of darwin and mingw ucrt.

Author: joshcooper

puppet.gemspec

@@ -32,17 +32,24 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency('semantic_puppet', '~> 1.0')
   spec.add_runtime_dependency('ostruct', '~> 0.6.0')
 
+  # If we're building a platform-specific gem, as indicated by spec.platform,
+  # include the corresponding runtime dependencies no matter which platform we're
+  # currently running on.
+  #
+  # If we're running in bundler, include runtime dependencies for the platform
+  # we're currently running on.
   platform = spec.platform.to_s
-  if platform == 'universal-darwin'
+  if platform =~ /darwin/ || (defined?(Bundler) && RUBY_PLATFORM =~ /darwin/)
     spec.add_runtime_dependency('CFPropertyList', ['>= 3.0.6', '< 4'])
   end
 
-  if (platform == 'x64-mingw32' || platform == 'x86-mingw32') || Gem.win_platform?
+  if platform =~ /mingw/ || (defined?(Bundler) && Gem.win_platform?)
     # ffi 1.16.0 - 1.16.2 are broken on Windows
     spec.add_runtime_dependency('ffi', '>= 1.15.5', '< 1.17.0', '!= 1.16.0', '!= 1.16.1', '!= 1.16.2')
     spec.add_runtime_dependency('minitar', '~> 0.9')
-  elsif !Gem.java_platform?
+  elsif platform =~ /java/ || (defined?(Bundler) && Gem.java_platform?)
     # don't depend on syslog on jruby, it requires extensions
+  else
     spec.add_runtime_dependency('syslog', '~> 0.1.2')
   end
 end