Re: PYTHONBIN for cross-compilation to different LOCALBASE

[Taylor R Campbell <campbell+netbsd-tech-pkg%mumble.net@localhost>]

> Date: Sun, 11 Jun 2023 21:15:45 -0400
> From: Greg Troxel <gdt%lexort.com@localhost>
> 
> My quick reaction is that
> 
>   PYTHONBIN should be for the target system, via lang/python/application.mk
> 
>   TOOL_PYTHONBIN should be for the build host via USE_TOOLS += python or
>   something like lang/python/tool.mk.
> 
> Of course some packages may use both.  Probably most python packages as
> py-culture is to run python programs to configure.

USE_TOOLS+=python isn't a thing (and the USE_TOOLS framework itself
poses a difficulty with TOOLBASE/LOCALBASE split, with things like
USE_TOOLS+=sed vs USE_TOOLS+=sed:run, to be addressed separately).

As you note, many Python packages use Python at build-time (e.g., to
run setup.py) _and_ at run-time (e.g., in #! lines), via just
pyversion.mk or application.mk.  These are the ones that need two
variables to make the distinction.

Question is, which use of the existing PYTHONBIN variable is more
prevalent?

Hoping to get a sense of this before committing to a new variable
scheme that ends up requiring a mass-change later like my mistake with
BUILD_DEPENDS and TOOL_DEPENDS.