Support workspace files with spaces in their names

Currently, the rules rely on passing workspace files to the child workspace using `runfiles`. However, a [known Bazel issue](https://github.com/bazelbuild/bazel/issues/4327) prevents files with spaces in their names from working properly. Ideally, this will be fixed in Bazel. However, for now, we may want to allow a client to specify whether to use an alternative mechanism.

Possible solutions:

1. Add the files to an archive file and pass that through runfiles
2. Create a mechanism that creates symlinks from a more robust file format as compared to the current, space-delimited format.

No file or test is named. Start by locating the rule or macro that passes workspace files to the child workspace through runfiles, then reproduce the failure with a filename containing spaces. Compare the archive and symlink alternatives described in the issue; done means workspace files with spaces work through a documented, selectable mechanism.

Written by the indexing model from the issue text.