I contribute to a decent-sized C++ project with a number of dependencies. The problem is, the project contains the source of all of its dependencies (e.g. pcre, zlib, etc.). I w
There's a fallacy in your statement: "I want to trim the project down to just what's relevant to the program itself."
Believe me, the dependencies are extremely relevant to the program. If you don't have these in source control then you will encounter no end of problems when introducing new team members or when switching to a new workstation.
Even if compile the "non-relevant" libraries, these compiled libraries should go into your source repository.