python/s3transfer: Added python3 support.

Signed-off-by: Dimitris Zlatanidis <d.zlatanidis@gmail.com>

Signed-off-by: Willy Sudiarto Raharjo <willysr@slackbuilds.org>

python/s3transfer/README

@@ -1 +1,5 @@
 S3transfer is a Python library for managing Amazon S3 transfers.
+
+Note: Dependency futures it does not work on Python 3,
+and Python 3 users do not need it as the concurrent.futures package
+is available in the standard library.

python/s3transfer/s3transfer.SlackBuild

@@ -71,6 +71,11 @@ find -L . \
 
 python setup.py install --root=$PKG
 
+# Python 3 support.
+if $(python3 -c 'import sys' 2>/dev/null); then
+  python3 setup.py install --root=$PKG
+fi
+
 find $PKG -print0 | xargs -0 file | grep -e "executable" -e "shared object" | grep ELF \
   | cut -f 1 -d : | xargs strip --strip-unneeded 2> /dev/null || true