diff --git a/libc/upstream-netbsd/android/include/netbsd-compat.h b/libc/upstream-netbsd/android/include/netbsd-compat.h
index ea630b2..5dd086e 100644
--- a/libc/upstream-netbsd/android/include/netbsd-compat.h
+++ b/libc/upstream-netbsd/android/include/netbsd-compat.h
@@ -17,7 +17,7 @@
 #pragma once
 
 #define _BSD_SOURCE
-#define _GNU_SOURCE
+#define _GNU_SOURCE 1
 
 // NetBSD uses _DIAGASSERT to null-check arguments and the like,
 // but it's clear from the number of mistakes in their assertions