The new set of tests iterates over Boost.Thread public headers and verifies that
each header is self-contained, i.e. doesn't have any missing includes and
contains syntactically correct content. On Windows and Cygwin, a second test
per each header is generated, which includes the header after windows.h. This
verifies that the header doesn't have conflicts with Windows SDK and that
includeing windows.h does not break platform detection in Boost.Thread.
This set of tests would have detected the bug fixed by
https://github.com/boostorg/thread/pull/263.