Cannot find MSVC 2019 build tools if installed with Visual Studio 2022

[ChrisDenton]

Reported here: rust-lang/rustup#3024

A brief investigation shows this line to be the problem:

cc-rs/src/windows_registry.rs

Lines 461 to 462 in 53272c5

	let version_path =
	instance_path.join(r"VC\Auxiliary\Build\Microsoft.VCToolsVersion.default.txt");

If the Visual Studio 2022 does not have the MSVC 2022 build tools then Microsoft.VCToolsVersion.default.txt may be missing. However, if MSVC 2019 is installed Microsoft.VCToolsVersion.v142.default.txt is present. Therefore a possible fix would be to fallback to searching for this and other variations on this file name.

EDIT: This appears to also be broadly true for any version other than latest.