Guard GOOGLE_PREDICT_TRUE|FALS with #ifndef to avoid collision with other google…

Guard GOOGLE_PREDICT_TRUE|FALS with #ifndef to avoid collision with other google opensource projects like protobuf.

src/glog/logging.h.in

@@ -129,15 +129,28 @@ typedef unsigned __int64 uint64;
 #ifndef GOOGLE_PREDICT_BRANCH_NOT_TAKEN
 #if @ac_cv_have___builtin_expect@
 #define GOOGLE_PREDICT_BRANCH_NOT_TAKEN(x) (__builtin_expect(x, 0))
-#define GOOGLE_PREDICT_FALSE(x) (__builtin_expect(x, 0))
-#define GOOGLE_PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
 #else
 #define GOOGLE_PREDICT_BRANCH_NOT_TAKEN(x) x
+#endif
+#endif
+
+#ifndef GOOGLE_PREDICT_FALSE
+#if @ac_cv_have___builtin_expect@
+#define GOOGLE_PREDICT_FALSE(x) (__builtin_expect(x, 0))
+#else
 #define GOOGLE_PREDICT_FALSE(x) x
+#endif
+#endif
+
+#ifndef GOOGLE_PREDICT_TRUE
+#if @ac_cv_have___builtin_expect@
+#define GOOGLE_PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
+#else
 #define GOOGLE_PREDICT_TRUE(x) x
 #endif
 #endif
 
+
 // Make a bunch of macros for logging.  The way to log things is to stream
 // things to LOG(<a particular severity level>).  E.g.,
 //
@@ -710,10 +723,10 @@ DEFINE_CHECK_OP_IMPL(Check_GT, > )
 // to reduce the overhead of CHECK statments by 2x.
 // Real DCHECK-heavy tests have seen 1.5x speedups.
 
-// The meaning of "string" might be different between now and 
+// The meaning of "string" might be different between now and
 // when this macro gets invoked (e.g., if someone is experimenting
 // with other string implementations that get defined after this
-// file is included).  Save the current meaning now and use it 
+// file is included).  Save the current meaning now and use it
 // in the macro.
 typedef std::string _Check_string;
 #define CHECK_OP_LOG(name, op, val1, val2, log)                         \