diff --git a/libc/upstream-netbsd/android/include/netbsd-compat.h b/libc/upstream-netbsd/android/include/netbsd-compat.h
index 665d65e..cc0f71f 100644
--- a/libc/upstream-netbsd/android/include/netbsd-compat.h
+++ b/libc/upstream-netbsd/android/include/netbsd-compat.h
@@ -25,6 +25,17 @@
 // that they don't actually test or ship with this.
 #define _DIAGASSERT(e) /* nothing */
 
+/*
+ * The following macro is used to remove const cast-away warnings
+ * from gcc -Wcast-qual; it should be used with caution because it
+ * can hide valid errors; in particular most valid uses are in
+ * situations where the API requires it, not to cast away string
+ * constants. We don't use *intptr_t on purpose here and we are
+ * explicit about unsigned long so that we don't have additional
+ * dependencies.
+ */
+#define __UNCONST(a)    ((void *)(unsigned long)(const void *)(a))
+
 // TODO: we don't yet have thread-safe environment variables.
 #define __readlockenv() 0
 #define __unlockenv() 0