placate flake8

Author: cclauss

tools/system_libs.py

@@ -503,7 +503,7 @@ def build_objects(self, build_dir):
     for src in self.get_files():
       ext = shared.suffix(src)
       if ext in {'.s', '.S', '.c'}:
-        cmd = shared.EMCC 
+        cmd = shared.EMCC
       else:
         cmd = shared.EMXX
       cmd = [cmd, '-c']