cmake -E: Add cmake_transform_depfile internal command

Source/CMakeLists.txt

Source/cmTransformDepfile.cxx

Source/cmTransformDepfile.h

Source/cmcmd.cxx

Tests/RunCMake/CMakeLists.txt

Tests/RunCMake/TransformDepfile/RunCMakeTest.cmake

Tests/RunCMake/TransformDepfile/deps-unix.d

Tests/RunCMake/TransformDepfile/deps-unix.d.txt

Tests/RunCMake/TransformDepfile/deps-unix.tlog.txt

Tests/RunCMake/TransformDepfile/deps-windows.d

Tests/RunCMake/TransformDepfile/deps-windows.d.txt

Tests/RunCMake/TransformDepfile/deps-windows.tlog.txt

Tests/RunCMake/TransformDepfile/empty.d

Tests/RunCMake/TransformDepfile/empty.d.txt

Tests/RunCMake/TransformDepfile/empty.tlog.txt

Tests/RunCMake/TransformDepfile/gccdepfile.cmake

Tests/RunCMake/TransformDepfile/invalid-gcc-result.txt

Tests/RunCMake/TransformDepfile/invalid-tlog-result.txt

Tests/RunCMake/TransformDepfile/invalid.d

Tests/RunCMake/TransformDepfile/noexist.d.txt