diff --git a/libc/bionic/strtold.cpp b/libc/bionic/strtold.cpp
index 5616cf7..c55dd61 100644
--- a/libc/bionic/strtold.cpp
+++ b/libc/bionic/strtold.cpp
@@ -32,7 +32,7 @@
 extern "C" int __strtorQ(const char*, char**, int, void*);
 
 long double strtold(const char* s, char** end_ptr) {
-#if __LP64__
+#if defined(__LP64__)
   long double result;
   __strtorQ(s, end_ptr, FLT_ROUNDS, &result);
   return result;