[rubygems/rubygems] Ignore Errno::EROFS errors when creating bundler.lock

Apparently old versions of MacOS would set `GEM_HOME` to a `/System`
folder, and trying to create a file there raises `Errno::EROFS`.

We ignore the error. Any permission issues should be better handled
further down the line.

https://github.com/rubygems/rubygems/commit/ef90c071d0

lib/bundler/process_lock.rb

@@ -12,7 +12,7 @@ module Bundler
         yield
         f.flock(File::LOCK_UN)
       end
-    rescue Errno::EACCES, Errno::ENOLCK, Errno::ENOTSUP, Errno::EPERM
+    rescue Errno::EACCES, Errno::ENOLCK, Errno::ENOTSUP, Errno::EPERM, Errno::EROFS
       # In the case the user does not have access to
       # create the lock file or is using NFS where
       # locks are not available we skip locking.

spec/bundler/install/process_lock_spec.rb

@@ -42,5 +42,16 @@ RSpec.describe "process lock spec" do
         expect(processed).to eq true
       end
     end
+
+    context "when creating a lock raises Errno::EROFS" do
+      before { allow(File).to receive(:open).and_raise(Errno::EROFS) }
+
+      it "skips creating the lock file and yields" do
+        processed = false
+        Bundler::ProcessLock.lock(default_bundle_path) { processed = true }
+
+        expect(processed).to eq true
+      end
+    end
   end
 end