Introduce a V8_NORETURN macro and use it to make GCC 4.9.2 happy again.

include/v8config.h

Index: include/v8config.h
diff --git a/include/v8config.h b/include/v8config.h
index fabf13b61a7e5d58b9db4f8e634d741f2d09e588..5685209141918f014ca1d980ced2e4564bf4da9f 100644
--- a/include/v8config.h
+++ b/include/v8config.h
@@ -171,6 +171,7 @@
 //                                        supported
 //  V8_HAS_ATTRIBUTE_DEPRECATED         - __attribute__((deprecated)) supported
 //  V8_HAS_ATTRIBUTE_NOINLINE           - __attribute__((noinline)) supported
+//  V8_HAS_ATTRIBUTE_NORETURN           - __attribute__((noreturn)) supported
 //  V8_HAS_ATTRIBUTE_UNUSED             - __attribute__((unused)) supported
 //  V8_HAS_ATTRIBUTE_VISIBILITY         - __attribute__((visibility)) supported
 //  V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT - __attribute__((warn_unused_result))
@@ -186,6 +187,7 @@
 //  V8_HAS_DECLSPEC_DEPRECATED          - __declspec(deprecated) supported
 //  V8_HAS_DECLSPEC_NOINLINE            - __declspec(noinline) supported
 //  V8_HAS_DECLSPEC_SELECTANY           - __declspec(selectany) supported
+//  V8_HAS_DECLSPEC_NORETURN            - __declspec(noreturn) supported
 //  V8_HAS___FINAL                      - __final supported in non-C++11 mode
 //  V8_HAS___FORCEINLINE                - __forceinline supported
 //
@@ -211,6 +213,7 @@
 # define V8_HAS_ATTRIBUTE_ALWAYS_INLINE (__has_attribute(always_inline))
 # define V8_HAS_ATTRIBUTE_DEPRECATED (__has_attribute(deprecated))
 # define V8_HAS_ATTRIBUTE_NOINLINE (__has_attribute(noinline))
+#define V8_HAS_ATTRIBUTE_NORETURN (__has_attribute(noreturn))
 # define V8_HAS_ATTRIBUTE_UNUSED (__has_attribute(unused))
 # define V8_HAS_ATTRIBUTE_VISIBILITY (__has_attribute(visibility))
 # define V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT \
@@ -249,6 +252,7 @@
 # define V8_HAS_ATTRIBUTE_DEPRECATED (V8_GNUC_PREREQ(3, 4, 0))
 # define V8_HAS_ATTRIBUTE_DEPRECATED_MESSAGE (V8_GNUC_PREREQ(4, 5, 0))
 # define V8_HAS_ATTRIBUTE_NOINLINE (V8_GNUC_PREREQ(3, 4, 0))
+#define V8_HAS_ATTRIBUTE_NORETURN (V8_GNUC_PREREQ(2, 5, 0))
 # define V8_HAS_ATTRIBUTE_UNUSED (V8_GNUC_PREREQ(2, 95, 0))
 # define V8_HAS_ATTRIBUTE_VISIBILITY (V8_GNUC_PREREQ(4, 3, 0))
 # define V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT \
@@ -291,6 +295,7 @@
 # define V8_HAS_DECLSPEC_DEPRECATED 1
 # define V8_HAS_DECLSPEC_NOINLINE 1
 # define V8_HAS_DECLSPEC_SELECTANY 1
+#define V8_HAS_DECLSPEC_NORETURN 1
 
 # define V8_HAS___FORCEINLINE 1
 
@@ -325,6 +330,18 @@
 #endif
 
 
+// A macro used to tell the compiler that a particular function never returns.
+// Use like:
+//   V8_NORETURN int MyAbort() { abort(); }
+#if V8_HAS_ATTRIBUTE_NORETURN
+#define V8_NORETURN __attribute__((noreturn))
+#elif HAS_DECLSPEC_NORETURN
+#define V8_NORETURN __declspec(noreturn)
+#else
+#define V8_NORETURN /* NOT SUPPORTED */
+#endif
+
+
 // A macro to mark classes or functions as deprecated.
 #if defined(V8_DEPRECATION_WARNINGS) && V8_HAS_ATTRIBUTE_DEPRECATED_MESSAGE
 # define V8_DEPRECATED(message, declarator) \