diff --git a/compiler-rt/test/Unit/endianness.h b/compiler-rt/test/Unit/endianness.h
index c4c6e06a95b6..a123acd2d148 100644
--- a/compiler-rt/test/Unit/endianness.h
+++ b/compiler-rt/test/Unit/endianness.h
@@ -72,7 +72,7 @@
 
 /* .. */
 
-#if defined(__Linux__)
+#if defined(__linux__)
 #include <endian.h>
 
 #if __BYTE_ORDER == __BIG_ENDIAN