diff --git a/setup.py b/setup.py
index fcf668bf7532b683605da9ceb34ed5cdf215a9d6..46666608d477607eca6847d72a0d73738c1f74e2 100644
--- a/setup.py
+++ b/setup.py
@@ -103,7 +103,7 @@ class BuildExt(build_ext):
         elif ct == 'msvc':
             opts.append('/DVERSION_INFO=\\"%s\\"' % self.distribution.get_version())
         for ext in self.extensions:
-            ext.extra_compile_args = opts
+            ext.extra_compile_args = ext.extra_compile_args + opts
         build_ext.build_extensions(self)
 
 # }}}