Set the VCPKG_INSTALLED_DIR, VCPKG_HOST_TRIPLET, VCPGK_TARGET_TRIPLET
environment variables after vcpkg ports installation. These variables
will be used when building Qt modules to setup the correct build
environment.
Change-Id: I3a625f4ef089b5da676b96a5bebaacfb09112ee4
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>