diff --git a/libc/bionic/fpclassify.cpp b/libc/bionic/fpclassify.cpp
index f8cea80..42ed3ef 100644
--- a/libc/bionic/fpclassify.cpp
+++ b/libc/bionic/fpclassify.cpp
@@ -113,7 +113,7 @@
 }
 __strong_alias(isnormalf, __isnormalf);
 
-#if __LP64__
+#if defined(__LP64__)
 
 // LP64 uses 128-bit long doubles.