diff --git a/src/fs/io/FileOutputStream.cxx b/src/fs/io/FileOutputStream.cxx
index f7d88d7fb..d0375fe0a 100644
--- a/src/fs/io/FileOutputStream.cxx
+++ b/src/fs/io/FileOutputStream.cxx
@@ -151,7 +151,7 @@ FileOutputStream::Commit()
 {
 	assert(IsDefined());
 
-#if HAVE_LINKAT
+#ifdef HAVE_LINKAT
 	if (is_tmpfile) {
 		unlink(GetPath().c_str());