No such file or directory at configure time

Problem: execution of imported target returns a No such file or directory message.

find_package( Python3 )

if( Python3_FOUND )
	execute_process(
		COMMAND Python3::Interpreter --version
		RESULT_VARIABLE res
		OUTPUT_VARIABLE out
	)
	message( "this message: ${res}" )
endif()

results in: this message: No such file or directory

The package is found correctly and its targets are accessible during build. It is just that, execute_process does not seem to have access to it.

My first thought was that execute_process does not have this target during configuration because it might be run before the package is found. This is why I added the _FOUND condition. I thought it would then run correctly in a second iteration at configure time. It did not.

I cannot see the call to python anywhere in my verbose build output.

everything works fine using the cache variable, instead of the target:

```cmake
find_package( Python3 )

if( Python3_FOUND )
	execute_process(
		COMMAND ${Python3_EXECUTABLE} --version
		RESULT_VARIABLE res
		OUTPUT_VARIABLE out
	)
	message( "this message: ${res}" )
endif()

This confirms that configure stage works as expected. It seems as if there was a problem with the imported target during configuration. Generally speaking, this shouldn’t be a problem, though.

execute_process does not support targets in the COMMAND option.