Fix ifdef complaints in clang

BUG=angle:677

Change-Id: Iee457dfc0990e5ffd61932b1f286f3c0208568bc
Reviewed-on: https://chromium-review.googlesource.com/203427
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Shannon Woods <shannonwoods@chromium.org>
diff --git a/src/common/utilities.cpp b/src/common/utilities.cpp
index c05871e..06ac723 100644
--- a/src/common/utilities.cpp
+++ b/src/common/utilities.cpp
@@ -433,7 +433,7 @@
 
 std::string getTempPath()
 {
-#if ANGLE_PLATFORM_WINDOWS
+#ifdef ANGLE_PLATFORM_WINDOWS
     char path[MAX_PATH];
     DWORD pathLen = GetTempPathA(sizeof(path) / sizeof(path[0]), path);
     if (pathLen == 0)