Fix usage of SK_BUILD_* defines.
Since we just 'define' them, but not attribute anything to them, like
'1' for example, cpp expands it to nothing and that breaks the "#if"
clauses.
To fix that, uses "#if defined(...)" which will correctly check if your
macro name was defined or not.
BUG=skia:2850
TEST=make most
R=robertphillips@google.com
Review URL: https://codereview.chromium.org/628763005
diff --git a/tools/skpdiff/skpdiff_main.cpp b/tools/skpdiff/skpdiff_main.cpp
index c01767e..92f1307 100644
--- a/tools/skpdiff/skpdiff_main.cpp
+++ b/tools/skpdiff/skpdiff_main.cpp
@@ -14,7 +14,7 @@
#define __NO_STD_VECTOR // Uses cl::vectpr instead of std::vectpr
#define __NO_STD_STRING // Uses cl::STRING_CLASS instead of std::string
-#if SK_BUILD_FOR_MAC
+#if defined(SK_BUILD_FOR_MAC)
// Note that some macs don't have this header and it can be downloaded from the Khronos registry
# include <OpenCL/cl.hpp>
#else