Move DumpBacktrace() to checks.cc and cleanup both the code and the necessary platform checks.

src/platform-macos.cc

Index: src/platform-macos.cc
diff --git a/src/platform-macos.cc b/src/platform-macos.cc
index a58bc1aca3943184d0185246c5498a060b90149b..5ffc3fc54c45adcbd7a7d2a47bdbc04d3ae52539 100644
--- a/src/platform-macos.cc
+++ b/src/platform-macos.cc
@@ -53,27 +53,15 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
-#include <cxxabi.h>
 
 #undef MAP_TYPE
 
 #include "v8.h"
 
-#include "platform-posix.h"
 #include "platform.h"
 #include "simulator.h"
 #include "vm-state-inl.h"
 
-// Manually define these here as weak imports, rather than including execinfo.h.
-// This lets us launch on 10.4 which does not have these calls.

[Michael Achenbach, 2013/09/23 11:12:50]

In the new code, execinfo.h will be included. Will it still work on 10.4?

[Benedikt Meurer, 2013/09/23 11:26:40]

Nope. We've moved to 10.6 as announced publicly last week.

-extern "C" {
-  extern int backtrace(void**, int) __attribute__((weak_import));
-  extern char** backtrace_symbols(void* const*, int)
-      __attribute__((weak_import));
-  extern void backtrace_symbols_fd(void* const*, int, int)
-      __attribute__((weak_import));
-}
-
 
 namespace v8 {
 namespace internal {
@@ -107,14 +95,6 @@ void* OS::Allocate(const size_t requested,
 }
 
 
-void OS::DumpBacktrace() {
-  // If weak link to execinfo lib has failed, ie because we are on 10.4, abort.
-  if (backtrace == NULL) return;
-
-  POSIXBacktraceHelper<backtrace, backtrace_symbols>::DumpBacktrace();
-}
-
-
 class PosixMemoryMappedFile : public OS::MemoryMappedFile {
  public:
   PosixMemoryMappedFile(FILE* file, void* memory, int size)