Fix build after r18344

src/assembler.cc

Index: src/assembler.cc
diff --git a/src/assembler.cc b/src/assembler.cc
index 0578c76fab63ca9cf32c8d3aedeb73ab7498d36a..1076be0271142cf60f878b332125df4baa5f4286 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -1388,10 +1388,15 @@ ExternalReference ExternalReference::address_of_regexp_stack_memory_size(
 #endif  // V8_INTERPRETED_REGEXP
 
 
+static double math_log_double(double x) {
+  return log(x);
+}
+
+
 ExternalReference ExternalReference::math_log_double_function(
     Isolate* isolate) {
   return ExternalReference(Redirect(isolate,
-                                    FUNCTION_ADDR(log),
+                                    FUNCTION_ADDR(math_log_double),
                                     BUILTIN_FP_CALL));
 }