cross-compiling and python

Hi,

there is currently only one configure option for python:
--enable-python=<no/auto/system/internal>

But we need python for more things and it seems to me like we would
need another one:
--enable-build-python=<system/internal>
because build-time python is used in filter/CustomTarget_svg.mk

Maybe it could work with only one option with implying:
--enable-python=system -> --enable-build-python=system
--enable-python=internal -> --enable-build-python=internal ? (we would
need to add python module to RepositoryModule_build.mk ?!)
--enable-python=no -> --enable-build-python=system ?

Or maybe we could just always use system python when building ?
Is it available everywhere ? It should be on Linux, Cygwin.. how about Mac ?

Anyhow, configure is quite messy regarding python, or at least I was
not able to decipher all the conditionals easily.
Maybe I could use --disable-python for now but at least I will need to
fix few places to use system build-time python.

Thanks,
Matus