I am looking for a license that would allow anyone to contribute to an open source project. That of course includes copying/forking the code and applying changes to it, that potentially (and maybe only partially) go back into the original source code via a review process. (pull-request on GitHub or similar processes) The sources itself are available on GitHub and as archived downloads from other sources.
Making builds for distribution should be exclusively reserved to the project owner. These builds are, just as the source code, available to everyone and free of charge and may also be redistributed by third parties for free. Usage of the software in commercial and non-commercial products is allowed and would require credit, however the builds itself can not be part of the price in commercial projects.
Creating customized builds or builds derived from the source code or available builds should not be allowed if these are going to be distributed in any form. Creating builds for the sole purpose of verifying that available builds are indeed created from the available source code may be allowed of course.