py-setuptools as a DEPENDS?

[Frédéric Fauberteau <triaxx%NetBSD.org@localhost>]

According to devel/py-setuptools/DESCR, this tool aims at building and 
distributing python package.

What about the following?
Index: egg.mk
===================================================================
RCS file: /cvsroot/pkgsrc/lang/python/egg.mk,v
retrieving revision 1.27
diff -u -r1.27 egg.mk
--- egg.mk      8 Feb 2017 12:09:30 -0000       1.27
+++ egg.mk      29 Aug 2018 08:02:55 -0000
@@ -50,7 +50,7 @@
 ensurepip:
        ${SETENV} ${MAKE_ENV} ${PYTHONBIN} -m ensurepip --user
 .else
-DEPENDS+=      ${PYPKGPREFIX}-setuptools>=0.8:../../devel/py-setuptools
+BUILD_DEPENDS+=        
${PYPKGPREFIX}-setuptools>=0.8:../../devel/py-setuptools
 .endif

 INSTALLATION_DIRS+=    ${PYSITELIB}