diff --git a/libc/kernel/tools/cpp.py b/libc/kernel/tools/cpp.py
index 0fd6e46..08b786a 100755
--- a/libc/kernel/tools/cpp.py
+++ b/libc/kernel/tools/cpp.py
@@ -2345,11 +2345,11 @@
 
     def test_function_keep_attribute_structs(self):
         text = """\
-static inline struct some_struct1 * function(struct some_struct2 * e) {
+static __inline__ struct some_struct1 * function(struct some_struct2 * e) {
 }
 """
         expected = """\
-static inline struct some_struct1 * function(struct some_struct2 * e) {
+static __inline__ struct some_struct1 * function(struct some_struct2 * e) {
 }
 """
         self.assertEqual(self.parse(text, set(["function"])), expected)