sol2 is a header-only library.
sol2 comes with a CMake script in the top level. It is primarily made for building and running the examples and tests, but it includes exported and configured targets (sol2, sol2_single) for your use. sol2::sol2 alias is defined for the sol2 target as well.
sol2 also comes with a Meson Script. If things stop working, file a bug report.