I tried to install ros galactic from source on ubuntu 18.04 but building fails at qt_binding. This is the error:

--- stderr: python_qt_binding                                           
Traceback (most recent call last):
  File "setup.py", line 10, in <module>
    d = generate_distutils_setup()
  File "/home/agx/.local/lib/python3.6/site-packages/catkin_pkg/python_setup.py", line 75, in generate_distutils_setup
    package = parse_package(package_xml_path)
  File "/home/agx/.local/lib/python3.6/site-packages/catkin_pkg/package.py", line 583, in parse_package
    xml, filename = _get_package_xml(path)
  File "/home/agx/.local/lib/python3.6/site-packages/catkin_pkg/package.py", line 516, in _get_package_xml
    raise IOError('Path "%s" is neither a directory containing a "%s" file nor a file' % (path, PACKAGE_MANIFEST_FILENAME))
OSError: Path "." is neither a directory containing a "package.xml" file nor a file
---

I dont know how to fix this