run-tests: support running tests in parallel on windows Previously, we used os.spawnvp, which doesn't exist on Windows, and isn't needed anyway (the command line begins with an absolute path). We also need a slightly more convoluted way to wait for processes without specifying an order on Windows, as it lacks os.wait.

makefile: allow local builds to work on windows/mingw32

check-code: make 'missing whitespace in assignment' more aggressive New warnings: > a.b=ab missing whitespace in assignment (the pattern did not accept '.' on the left hand side) > a=a missing whitespace in assignment (the right hand side pattern never matched a single character) > a=a + 7 missing whitespace in assignment (the pattern only matched one character after the identifier following =)