[gentoo-dev] [RFC] Common build directory variable (for cmake-utils & autotools-utils)

[Michał Górny]

Hello,

The new python-r1 eclass provides a python_foreach_impl() function
which runs given command for each python implementation, in its
respective build directory.

This function collides a bit with the build-dir functionality provided
in cmake-utils and autotools-utils. If used to spawn the phase
functions of those eclasses, it first enters the correct (python
implementation-specific) build directory, then the eclass re-enters its
own, chosen build directory.

In order to work-around that, users either have to:

a) wrap all phase functions in custom wrapper which set CMAKE_BUILD_DIR
or AUTOTOOLS_BUILD_DIR,

b) use cheap tricks like setting CMAKE_BUILD_DIR=. globally (untested).

Both solutions being not really that good, I think it would be useful
to use a common BUILD_DIR variable for all eclasses. In that case,
python-r1 would just set BUILD_DIR, and cmake-utils or autotools-utils
phase functions would just use that instead of FOO_BUILD_DIR.

What are your thoughts?

-- 
Best regards,
Michał Górny