diff --git a/setup.py b/setup.py
index 19a2934..a74ca72 100755
--- a/setup.py
+++ b/setup.py
@@ -298,6 +298,7 @@ class CustomBuildExt(build_ext):
                 e.extra_compile_args.append("-Wdeclaration-after-statement")
                 e.extra_compile_args.append("-Werror=declaration-after-statement")
                 e.extra_compile_args.append("-O3")
+                e.extra_compile_args.append("-std=gnu99")
 
 
         # build in place, and in the build/ tree