CMake toolchain file - use list(APPEND

[rpavlik]

https://github.com/Microsoft/vcpkg/blob/48c4b79be510c5aff3f28079b7875a95497691e5/scripts/buildsystems/vcpkg.cmake#L131

That line is inside of a loop and just appends directories to a list. Doing so using set(VAR ${VAR} NewThing) is much less efficient (slower CMake execution) than the equivalent list(APPEND VAR NewThing) command.

Thus replacing the block with

list(APPEND CMAKE_PROGRAM_PATH "${_VCPKG_INSTALLED_DIR}/${VCPKG_TARGET_TRIPLET}/tools")
file(GLOB _VCPKG_TOOLS_DIRS "${_VCPKG_INSTALLED_DIR}/${VCPKG_TARGET_TRIPLET}/tools/*")
foreach(_VCPKG_TOOLS_DIR ${_VCPKG_TOOLS_DIRS})
    if(IS_DIRECTORY "${_VCPKG_TOOLS_DIR}")
        list(APPEND CMAKE_PROGRAM_PATH "${_VCPKG_TOOLS_DIR}")
    endif()
endforeach()

would provide some speedup in cmake/config time. (Might be measurable speedup, especially if there are a lot of things in the tools directory)

You'll note I also added quotes around things that might have spaces in their expansion: CMake isn't as fragile as Make with spaces, but I think in at least some of those cases, a space in the path might mess things up, so I tend to err on the side of caution and quote paths in CMake.