diff --git a/libc/include/android/api-level.h b/libc/include/android/api-level.h
index bcddddd..40846fb 100644
--- a/libc/include/android/api-level.h
+++ b/libc/include/android/api-level.h
@@ -151,6 +151,9 @@
 /** Names the "S" API level (31), for comparison against `__ANDROID_API__`. */
 #define __ANDROID_API_S__ 31
 
+/* This file is included in <features.h>, and might be used from .S files. */
+#if !defined(__ASSEMBLY__)
+
 /**
  * Returns the `targetSdkVersion` of the caller, or `__ANDROID_API_FUTURE__` if
  * there is no known target SDK version (for code not running in the context of
@@ -167,7 +170,7 @@
 
 #if __ANDROID_API__ < 29
 
-// android_get_device_api_level is a static inline before API level 29.
+/* android_get_device_api_level is a static inline before API level 29. */
 #define __BIONIC_GET_DEVICE_API_LEVEL_INLINE static __inline
 #include <bits/get_device_api_level_inlines.h>
 #undef __BIONIC_GET_DEVICE_API_LEVEL_INLINE
@@ -185,6 +188,8 @@
 
 #endif
 
+#endif /* defined(__ASSEMBLY__) */
+
 __END_DECLS
 
 /** @} */