gcc parameter -mcrtdll= for choosing Windows C RunTime DLL library

[Eli Zaretskii]

> Date: Sun, 20 Nov 2022 16:04:11 +0100
> From: Pali Rohár <pali.rohar@gmail.com>
> Cc: gcc@gcc.gnu.org, mingw-w64-public@lists.sourceforge.net
> 
> On Sunday 20 November 2022 16:45:55 Eli Zaretskii wrote:
> > > Date: Sun, 20 Nov 2022 13:53:48 +0100
> > > From: Pali Rohár via Gcc <gcc@gcc.gnu.org>
> > > 
> > Linking a program against a specific runtime means the produced binary will
> > not run on Windows systems older than the one where it was linked.  Why is
> > such a limitation a good idea, may I ask?
> 
> It will run also on older Windows system if you install redistributable
> runtime library. Which in most cases is already installed because other
> programs use it.

Installing a redistributable is a nuisance, and dependence on non-system
libraries might make the program non-free.

> And why you want a new version? Because of better C99/C11 support which
> is in ucrtbase.dll

That comes with a price, though.

> Note that with this option, you can also choose older version than the
> default one (WinXP msvcrt.dll). So e.g. you can choose msvcrt20.dll or
> crtdll.dll for older Windows version.

Using the OS default MSVCRT already gets me that, at zero cost.