Use-case: We have one repository for multiple operating systems, but different Jenkins jobs per operating system. Each job wants to get triggered if it's platform-specific files got modified, but not when the other platforms got modified.
We should be able to specify multiple filespec entries, where a filespec entry could be a fully-specified path, or a path containing a wildcard.
http://stackoverflow.com/q/5243593/14731 shows there is demand for this, but I'm using Mercurial instead of git. This feature should really apply across all SCMs.
This feature will require additional improvements in SCM plugins in any case.
Git, Perforce and SVN plugins already support the feature.
I'd recommend to start from a new JIRA issue with a feature request to Mercurial plugin.
I think the "universal" feature could be implemented in SCM API plugin. Probably, has been already implemented
https://wiki.jenkins-ci.org/display/JENKINS/SCM+API+Plugin