On Windows, when path is specified as absolute for cmdl argument, cmake can
interpret parts of the path as invalid escape chars. For example "C:\Users\..."
will result in "Invalid character escape '\U'." Externally specified
paths should be converted into cmake's representation, which uses '/'.
This can be done e.g. by using 'get_filename_component()'. Currently
there doesn't seem to be any problem with this, but let's add a test for
this.
Suggested-by: Ivan Grokhotkov <ivan@espressif.com>
Signed-off-by: Frantisek Hrbata <frantisek.hrbata@espressif.com>