Microsoft's Universal CRT, present by default in Windows 10, and installable on Windows 7 SP1 and later. Linking to UCRT using an entirely FOSS toolchain is, a

Microsoft's Universal CRT, present by default in Windows 10, and installable on Windows 7 SP1 and later. Linking to UCRT using an entirely FOSS toolchain is, alas, nontrivial, but supported by mingw compilers (gcc and clang; no idea about the various FOSS Fortran compilers): https://mingwpy.github.io/ucrt.html https://mingwpy.github.io/ucrt.html