diff --git a/build.py b/build.py
index ee6a7e1..b648cf9 100644
--- a/build.py
+++ b/build.py
@@ -159,6 +159,8 @@ def dequote(value):
                     'install',
                     '--prefix=',
                     '--target=.',
+                    '--python-version={}'.format(runtime[6:]),
+                    '--only-binary=:all:',
                     '--requirement=requirements.txt',
                 )