[Boost-build] building with b2 and mingw

Subject: [Boost-build] building with b2 and mingw
From: Robert Ramey (ramey_at_[hidden])
Date: 2017-02-03 23:31:38

What is he secret sauce to get a library to build/test with mingw.  I'm 
trying to do it on Appveyor so I can the error messages.  Right now I'm 
using:

# Copyright 2016 Peter Dimov
# Copyright 2016 Robert Ramey
# Distributed under the Boost Software License, Version 1.0.
# (See accompanying file LICENSE_1_0.txt or copy at 
http://boost.org/LICENSE_1_0.txt)

version: 1.0.{build}-{branch}

shallow_clone: true

branches:
   only:
     - develop
#    - master

install:
   - cd ..
   - git clone -b %APPVEYOR_REPO_BRANCH% 
https://github.com/boostorg/boost.git boost-root
   - cd boost-root
   - git submodule init libs/align
   - git submodule init libs/array
<snip> ...
   - git submodule init tools/build
   - git submodule update
   - xcopy /s /e /q %APPVEYOR_BUILD_FOLDER% libs\serialization
   - set PATH=C:\MinGW\bin;%PATH%
   - bootstrap mingw
   - tools\build\v2\b2 headers

build: off

test_script:
   - cd libs/serialization/test
   - tools\build\v2\b2 toolset=gcc link=static,shared

but it's failing at:

set PATH=C:\MinGW\bin;%PATH%
bootstrap mingw
Building Boost.Build engine
Failed to build Boost.Build engine.
Please consult bootstrap.log for further diagnostics.

If anyone has any information on this, I'd like to know about it.

Robert Ramey