Avoid name clashes of builtins and runtime functions.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 680a3f738abd3f5ad0e620b8162a56a67523280d..3fb7e473991bf2e84f310154c08fd4f70637cd55 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -7845,7 +7845,7 @@ RUNTIME_FUNCTION(Runtime_MathAtan2) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_MathExp) {
+RUNTIME_FUNCTION(Runtime_MathExpRT) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_exp()->Increment();
@@ -7856,7 +7856,7 @@ RUNTIME_FUNCTION(Runtime_MathExp) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_MathFloor) {
+RUNTIME_FUNCTION(Runtime_MathFloorRT) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_floor()->Increment();
@@ -7951,7 +7951,7 @@ RUNTIME_FUNCTION(Runtime_RoundNumber) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_MathSqrt) {
+RUNTIME_FUNCTION(Runtime_MathSqrtRT) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   isolate->counters()->math_sqrt()->Increment();