It takes too long to compile boost copy files using Vcpkg on Windows platform

[EndoSakura]

Because of this submission https://github.com/boostorg/build/commit/77a9d5d406ad1183ca3041155094e2c9497dee20 。After compiling boost, it will take a lot of time to copy /b copy the source files.

[EndoSakura]

jamxxx.bat ‘s content is