Building toolchain *and then* packages with vcpkg

[solemnwarning]

Hi all,

I'm not sure if this is possible vcpkg currently, or if its too zany to even be considered as a feature, but thought it might be worth discussing here in case it would be useful to anyone else.

One of my projects makes use of EnlyzeWinCompatLib for 32-bit Windows builds to produce executables that can be run on no-longer-supported Windows versions. EnlyzeWinCompatLib provides a set of compatibility shims and a custom build of libc++ which is used in favour of the MSVC C++ runtime.

My VS solution includes a project which downloads and builds EnlyzeWinCompatLib and another project which bootstraps vcpkg and installs required packages (using a custom triplet file to use Clang and EnlyzeWinCompatLib) after the first has finished.

So my question is whether the building of EnlyzeWinCompatLib (and its internal libc++/libwinpthreads) could cleanly be handled by vcpkg prior to building the dependencies? This would be somewhat useful for me since I already have a vcpkg cache set up, and thus the CI job wouldn't have to recompile libc++ every time.

For reference, the project is rehex (look under msvc/ for the solution) and the triplet in use is x86-windows-static-enlyze.cmake.

[Neumann-A]

#42129 which basically works without msvc being installed and you want something similar just with your compat lib.

basically you can inject a port dependency via vcpkg-cmake on the host side of things.

Is it clean? No, for a clean handling of this solution something like VCPKG_IMPLICT_PORT_DEPENDENCIES would be needed as a triplet variable to inject prebuild implicit dependencies like a compiler/toolchain. The alternative would be to introduce an compiler metaport which can be overriden by users as an injection point.