Contribution to Angstrom, where do I send patches to for buildsystem related issues?

Angstrom is using OpenEmbedded as buildsystem and heavily uses its layer features. Let’s take the v2012.05 release (which matches the yocto 1.2 (‘denzil’) release) as an example. All layers have their patch submission policy documented in a README file in each layer. Here is a summary of those:

For the specific example of the v2012.05 release there are some extra steps involved since only backports are allowed in the release branches of the various layers. Whenever possible do your patch on the ‘next’ branch of the setup-scripts to track the latest upstream and then get it accepted upstream and ask for a backport to the matching release branch. Policy on that varies, but adding a ‘[for-denzil]’ tag to your emails will usually do the trick.

Of the above layers only the meta-angstrom layer is controlled by angstrom developers, all other layers are out of angstrom control.