codemod: use pycompat.iswindows This is done by: sed -i "s/pycompat\.osname == 'nt'/pycompat.iswindows/" **/*.py sed -i "s/pycompat\.osname != 'nt'/not pycompat.iswindows/" **/*.py sed -i 's/pycompat.osname == "nt"/pycompat.iswindows/' **/*.py Differential Revision: https://phab.mercurial-scm.org/D1034

pycompat: define operating system constants As suggested by Ryan in D1019, it's cleaner if we use defined constants instead of `osname == 'nt'` everywhere. Differential Revision: https://phab.mercurial-scm.org/D1033