Rollback trunk to 3.21.16.2

src/platform.h

Index: src/platform.h
diff --git a/src/platform.h b/src/platform.h
index e0e62fa0237d6581e586a4d7098810986311266a..ee8fb92910be295b2dc68c711be979adf7388ec6 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -67,8 +67,6 @@ int signbit(double x);
 
 int strncasecmp(const char* s1, const char* s2, int n);
 
-// Visual C++ 2013 and higher implement this function.
-#if (_MSC_VER < 1800)
 inline int lrint(double flt) {
   int intgr;
 #if V8_TARGET_ARCH_IA32
@@ -86,8 +84,6 @@ inline int lrint(double flt) {
   return intgr;
 }
 
-#endif  // _MSC_VER < 1800
-
 #endif  // V8_CC_MSVC
 
 namespace v8 {
@@ -268,6 +264,8 @@ class OS {
     char text[kStackWalkMaxTextLen];
   };
 
+  static int StackWalk(Vector<StackFrame> frames);
+
   class MemoryMappedFile {
    public:
     static MemoryMappedFile* open(const char* name);