Environment

Description

Lots of software uses GNU autoconf or build systems written in POSIX shell. Typically, these use msys/cygwin to run on Windows at all (otherwise they couldn't support Windows). However, performance is extremely low. Essentially, Windows is missing a well-integrated POSIX environment, and the emulation done by Cygwin is, in many situations, extremely slow.

Please note that WSL does not solve the problem in general. It's not well-integrated, but it's more like a VM (WSL2 is literally a VM). A solution that is well-integrated is required. POSIX shell execution is actually only an example. Any project that makes use of POSIX, a standard for portable OS access, suffers from win32's non-orthogonal mess, that makes porting to Windows a nightmare. Even projects supported by Microsoft suffer from this problem. For example, consider: https://github.com/PowerShell/openssh-portable/blob/latestw_all/contrib/win32/win32compat/fileio.c https://github.com/PowerShell/openssh-portable/blob/latestw_all/contrib/win32/win32compat/w32fd.c.

It should not be necessary for every program to invent a POSIX compat. layer for Windows, which will be slow (as win32 does not provide the required capabilities). This will generally reduce the Windows experience, and it's Microsoft's responsibility to offer a better solution.

Steps to reproduce

A good test is running ffmpeg's configure program. FFmpeg is well-known enough, so no further description is necessary. However, it affects a lot of other projects.

Expected behavior

POSIX shell execution is as fast as on Linux.

Actual behavior

POSIX shell execution is several magnitudes slower than native or even virtualized Linux.