[Issue 19760] Windows 10 -m64 completely broken, can't compile/run hello world

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19760

--- Comment #17 from anonymous4 <dfj1esp02 at sneakemail.com> ---
(In reply to kinke from comment #16)
> Universal CRT is one part of the newer MS runtimes since 2015 (and so used
> when linking against recent MS msvcrt.lib or libcmt.lib). It doesn't solve
> anything for us (as it isn't preinstalled on older Windows; not sure if it's
> preinstalled on Win10)
It's delivered as system update to everything post XP.

> The problem isn't only with math functions (e.g., no hex float parsing,
> buggy snprintf in older MS runtimes...).
These two must be standalone too. UCRT has standard snprintf, then there's a
problem if some code actually relies on the buggy one.

> And in contrast to all/most? other
> x86(_64) runtimes, Microsoft chose 64-bit double precision for `long
> double`, so printf etc. from other runtimes won't work out of the box.
AFAIK, musl doesn't predefine fp precision and relies on declared precision
definitions.

Options:
1. keep using 100 or ms static lib
2. full static musl with ported malloc, stdio, personality, startup etc.
3. use ucrt and ported personality

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