John,
Have you confirmed that it is actually this commit that is causing the failure?
Like you, " I don't understand why it would impact on other libraries at all?"
No, and I'm unable to run the tests in /status/ either with or without the new config test present, I get some typically inscrutable Boost.Build errors: M:/data/boost/boost/tools/build/src/build\property.jam:740: in class@property-map.find from module object(property-map)@255 error: Ambiguous key M:/data/boost/boost/tools/build/src/build\type.jam:333: in generated-target-ps from module type M:/data/boost/boost/tools/build/src/build\type.jam:270: in type.generated-target -suffix from module type M:/data/boost/boost/tools/build/src/build\virtual-target.jam:505: in virtual-target.add-prefix-and-suffix from module virtual-target M:/data/boost/boost/tools/build/src/build\virtual-target.jam:464: in _adjust-name from module object(file-target)@98264 M:/data/boost/boost/tools/build/src/build\virtual-target.jam:253: in abstract-file-target.__init__ from module object(file-target)@98264 M:/data/boost/boost/tools/build/src/build\virtual-target.jam:557: in class@file-target.__init__ from module object(file-target)@98264 M:/data/boost/boost/tools/build/src/kernel\class.jam:90: in class.new from module class How do I checkout the same tree as is used for testing? John.