devel/py-pep8 conflicts with itself built against different versions of python

[Aleksej Lebedev <root%zta.lk@localhost>]

Hi,

Recently I added py-conan to wip. I was able to build it against all 
supported pythons (27, 34-37) using pkgsrc-2018Q4.
When I switched to pkgsrc-2019Q1 an extra dependency appeared: 
devel/py-lint -> ... -> devel/py-pep8.

devel/py-pep8 however doesn't support ALTERNATIVES yet.

I fixed it so now it works. Please consider the following patch:

mmpos@mmpos-server:/ubuntu-bionic/usr/pkgsrc/devel$ /pkg/bin/cvs diff -c 
3 py-pep8
? py-pep8/ALTERNATIVES
cvs diff: I know nothing about 3
cvs diff: Diffing py-pep8
Index: py-pep8/Makefile
===================================================================
RCS file: /cvsroot/pkgsrc/devel/py-pep8/Makefile,v
retrieving revision 1.9
diff -c -r1.9 Makefile
*** py-pep8/Makefile	25 Oct 2017 03:55:44 -0000	1.9
--- py-pep8/Makefile	1 May 2019 15:03:27 -0000
***************
*** 12,17 ****
--- 12,20 ----

  USE_LANGUAGES=	# none

+ post-install:
+ 	cd ${DESTDIR}${PREFIX}/bin && ${MV} pep8 pep8-${PYVERSSUFFIX}
+
  do-test:
  	cd ${WRKSRC}; ${SETENV} ${TEST_ENV} ${PYTHONBIN} setup.py test

Index: py-pep8/PLIST
===================================================================
RCS file: /cvsroot/pkgsrc/devel/py-pep8/PLIST,v
retrieving revision 1.2
diff -c -r1.2 PLIST
*** py-pep8/PLIST	26 Apr 2014 11:09:24 -0000	1.2
--- py-pep8/PLIST	1 May 2019 15:03:27 -0000
***************
*** 1,5 ****
  @comment $NetBSD: PLIST,v 1.2 2014/04/26 11:09:24 wen Exp $
! bin/pep8
  ${PYSITELIB}/${EGG_INFODIR}/PKG-INFO
  ${PYSITELIB}/${EGG_INFODIR}/SOURCES.txt
  ${PYSITELIB}/${EGG_INFODIR}/dependency_links.txt
--- 1,5 ----
  @comment $NetBSD: PLIST,v 1.2 2014/04/26 11:09:24 wen Exp $
! bin/pep8-${PYVERSSUFFIX}
  ${PYSITELIB}/${EGG_INFODIR}/PKG-INFO
  ${PYSITELIB}/${EGG_INFODIR}/SOURCES.txt
  ${PYSITELIB}/${EGG_INFODIR}/dependency_links.txt


--
Aleksej Lebedev