Define %python2 and %python3

See https://pagure.io/packaging-committee/issue/907

Redefine %__pythonX to change the behavior of %pythonX, %pythonX_version, etc.
Use %pythonX in spec.

macros.python-srpm

@@ -2,9 +2,15 @@
 # - they can be used in Build/Requires
 # - they can be used in non-Python packages where requiring pythonX-devel would
 #   be an overkill
+
+# use the underscored macros to redefine the behavior of %%python3_version etc.
 %__python2 /usr/bin/python2
 %__python3 /usr/bin/python3
 
+# use the non-underscored macros to refer to Python in spec, etc.
+%python2 %__python2
+%python3 %__python3
+
 # python3_pkgversion specifies the version of Python 3 in the distro.  It can be
 # a specific version (e.g. 34 in Fedora EPEL7)
 %python3_pkgversion 3

python-rpm-macros.spec

@@ -1,6 +1,6 @@
 Name:           python-rpm-macros
 Version:        3
-Release:        42%{?dist}
+Release:        43%{?dist}
 Summary:        The unversioned Python RPM macros
 
 License:        MIT
@@ -73,6 +73,9 @@ install -m 644 %{SOURCE0} %{SOURCE1} %{SOURCE2} %{SOURCE3} %{SOURCE4} \
 
 
 %changelog
+* Fri Sep 27 2019 Miro Hrončok <mhroncok@redhat.com> - 3-43
+- Define %%python2 and %%python3
+
 * Sat Feb 02 2019 Fedora Release Engineering <releng@fedoraproject.org> - 3-42
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_30_Mass_Rebuild