MSys2 emulates pseudo terminals via named pipes, and isatty() returns 0
for such file descriptors. Therefore, some interactive functionality (such
as launching a pager, asking if a failed unlink should be repeated etc.)
doesn't work when run in a terminal emulator that uses MSys ptys (such as
mintty).
However, MSys uses special names for its pty pipes ('msys-*-pty*'), which
allows us to distinguish them from normal piped input / output.
On startup, check if stdin / stdout / stderr are connected to such pipes
using the NtQueryObject API from NTDll.dll. If the names match, adjust the
flags in MSVCRT's ioinfo structure accordingly.
Signed-off-by: Karsten Blees <blees@dcon.de>
c1ab43557e