Several suggestions

[JeffMill]

1. message("Bootstrapping vcpkg in ${VCPKG_ROOT}") should read message(STATUS "Bootstrapping vcpkg in ${VCPKG_ROOT}")
2. execute_process(COMMAND ${VCPKG_BOOTSTRAP} WORKING_DIRECTORY ${VCPKG_ROOT}) could include -disableMetrics , i.e. execute_process(COMMAND ${VCPKG_BOOTSTRAP} -disableMetrics WORKING_DIRECTORY ${VCPKG_ROOT}). Perhaps make it a configuration parameter?
3. (nit) You should set your editor to trim trailing whitespace at end of line.

Thanks! Great product.