x86_64-pc-windows-* is first and foremost a _misnomer_. The format of a configuration triplet (or quadruplet) is set in stone: MACHINE-VENDOR-[KERNEL-]OS.
Given that the MinGW ABI does not constitute the GNU operating system executing on the MS-Windows kernel, and MSVC is not an operating system, such blunders should be ignored, or at least normalized to one of the existing operating system values: x86_64-pc-mingw* for MinGW, and x86_64-pc-winnt for MSVC.
