Autodiscovered Python will be used for building even if it is of different bitness

[Kojoley]

32bit Python is installed in C:\Python27, but b2 address-model=64 toolset=msvc-14.1 python tries build it, and of course fails:

C:\Python27\libs\python27.lib : warning LNK4272: library machine type 'x86' conflicts with target machine type 'x64'
bin.v2\libs\python\build\msvc-14.1\debug\address-model-64\python-2.7\threading-multi\boost_python27-vc141-mt-gd-x64-1_70.dll : fatal error LNK1120: 135 unresolved externals

The reverse problem (64bit Python and 32bit MSVC) seems to happen on regression matrix https://www.boost.org/development/tests/develop/developer/output/BI-msvc-14-0-boost-bin-v2-libs-python-test-andreas_beyer-test-msvc-14-0-dbg-pythn-2-7-thrd-mlt.html

[Kojoley]

Probably Python launcher py can be used to find a correct one.

>py -0
Installed Pythons found by py Launcher for Windows
 -3.7-64 *
 -3.6-64
 -3.5-64
 -2.7-64
 -2.7-32

[stale[bot]]

Thank you for your contributions. Main development of B2 has moved to https://github.com/bfgroup/b2 This issue has been automatically marked as "transition" to indicate the potential for needing transition to the new B2 development project.