Cloud solution for cross-platform debugging

I am a contributor to an open-source C++ project that receives fairly frequent reports of platform-specific bugs. (E.g., "does not compile on the latest version of [Mac OS X / Debian / Ubuntu / random OS I've never heard of]", "does not run correctly with the latest version of ghostscript on [platform X]", ...) Unless I am very much mistaken, the project does not have the resources to get physical access to a computer running the same platform as the bug reporter.

Is there a cloud testing service/solution that would allow a developer to compile and debug the project on specific OS (and version of that OS, version of specific software, etc.) she would not otherwise have access to?

Notes:

• The service would need to have a low-cost or free version in order to be useful for the project in question.
• The GUI aspects of the project are secondary. It's mainly a commandline utility.