Need to build python3 as well as python2 version of some packages

Explanation in the added commend under buildopts.rpms.macros.

python2.yaml

@@ -65,6 +65,9 @@ data:
     filter:
         rpms:
             - python2-tkinter
+            - python3-wheel
+            - python3-setuptools
+            - python3-pip
     api:
         rpms:
             - python2
@@ -78,10 +81,17 @@ data:
     buildopts:
         rpms:
             macros: |
-                # setuptools & pip & wheel
-                %_without_python3 1
                 # setuptools
                 %_without_platform_python 1
+
+                # Note that we cannot disable building of Python 3 subpackages,
+                # because python2-devel (needed to build all Python 2 packages)
+                # has a runtime dependency on python3-rpm-generators, and that
+                # package requires python3-setuptools at runtime. By rebuilding
+                # python-setuptools SRPM with only python2, we overshadow the
+                # already built python3 subpackage and it is no longer
+                # available for python3-rpm-generators when building python-pip
+                # (or any other Python package).
     components:
         rpms:
             python-wheel: