CMake recipes place binaries in project root dir

[jimklimov]

The autotools recipes place binaries under src/ and some projects' manually written test code or scripts usually expect such layout. The CMake recipes place binaries into the workspace root directory.

At best, it makes porting recipes and ci_build.sh logic between toolchains more difficult than it could be, and pollutes the not-gitignored outputs. At worst, it might have to make project source codes to have to adapt to several toolchains nuances.

It would be desirable for both of these to perform in a similar manner, transparently to application projects' sources and recipes (at least the manually written part).