cmFileCommand: Fix build on mingw-w64

Include header needed for `CP_ACP`.
Status Job ID Name Coverage
  External
passed ghostflow-branch-check-master

passed ghostflow-commit-check

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager