Replace the @PYTHONSHEBANG@ substitution with a valid #!/usr/bin/python3
shebang. This turns Python .in files into valid Python files. The files
can now be checked with pylint and IDEs recognize the files as Python
files.
The shebang is still replaced with "#!$(PYTHON) -E" to support
platform-python.
Related: https://pagure.io/freeipa/issue/7984
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Francois Cami <fcami@redhat.com>