Merge branch 'js/mingw-isatty'

We often decide if a session is interactive by checking if the standard I/O streams are connected to a TTY, but isatty() emulation on Windows incorrectly returned true if it is used on NUL (i.e. an equivalent to /dev/null). This has been fixed. * js/mingw-isatty: mingw: intercept isatty() to handle /dev/null as Git expects it