`CMAKE_AR` and `CMAKE_RANLIB` do not accept a command with arguments

A while back I found this post that talks about cross compiling with zig. They said that doing it with CMake is left as an exercise to the reader, so I tried. The way it works is that your compiler becomes:

zig cc -target aarch64-linux-gnu

Eventually I found in the documentation of CMAKE_<LANG>_COMPILER that you can do this like so:

set(CMAKE_C_COMPILER "zig" cc -target aarch64-linux-gnu)
set(CMAKE_CXX_COMPILER "zig" c++ -target aarch64-linux-gnu)

Doing this configures everything correctly (it detects Clang 13 as expected), but then gives an error because CMAKE_AR (and CMAKE_RANLIB) are not set. These exist in the form of zig ar and zig ranlib, so I did:

set(CMAKE_AR "zig" ar)
set(CMAKE_RANLIB "zig" ranlib)

Unfortunately this results in a compilation error (configuring is fine):

error: unknown command: ;ar

I put a full example here: https://gitlab.kitware.com/mrexodia/cmake-zig

Let me know if anyone has any pointers where I can look to fix this in CMake, for now I found a workaround but it would be awesome if zig worked out of the box with CMake.