cmake: use -E remove_directory instead of -E rm
The rm command was introduced in 3.17, so let's go with the deprecated remove_directory instead to support e.g. Ubuntu 20.04 LTS.
Closes #240 (closed).
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The rm command was introduced in 3.17, so let's go with the deprecated remove_directory instead to support e.g. Ubuntu 20.04 LTS.
Closes #240 (closed).