Merge pull request #746 from zmodem/fix_predict_macros2

Fix the no-op definitions of GOOGLE_PREDICT_{TRUE,FALSE}

src/google/protobuf/stubs/port.h

@@ -193,7 +193,7 @@ static const uint64 kuint64max = GOOGLE_ULONGLONG(0xFFFFFFFFFFFFFFFF);
 // Provided at least since GCC 3.0.
 #define GOOGLE_PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
 #else
-#define GOOGLE_PREDICT_TRUE
+#define GOOGLE_PREDICT_TRUE(x) (x)
 #endif
 #endif
 
@@ -202,7 +202,7 @@ static const uint64 kuint64max = GOOGLE_ULONGLONG(0xFFFFFFFFFFFFFFFF);
 // Provided at least since GCC 3.0.
 #define GOOGLE_PREDICT_FALSE(x) (__builtin_expect(x, 0))
 #else
-#define GOOGLE_PREDICT_FALSE
+#define GOOGLE_PREDICT_FALSE(x) (x)
 #endif
 #endif