Earlier quoted context omitted.
That's ok for the NSA and a few large enterprises to check certain binaries but you can't ask any start up or small company to recompile themselves every version of every OS / Software / Library that they use. It's not really a practical solution (even assuming everything is open source).
As I posted above, we have a build service that does this automatically for you. It takes maybe 30 minutes to create a few spec files, and now it's supported by a bunch of different distributions. You can then point your users at the repo (or mirror the repo if you prefer). Also OBS lets you create forks of projects that just inherit the unmodified packages (and said forks can also be cross-host so you don't need to…
[edit] also that protects you against malware injecting binaries in an executable when compiling it, but not from malware injecting code into the source code of the executable.