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

src/platform-linux.cc

Index: src/platform-linux.cc
diff --git a/src/platform-linux.cc b/src/platform-linux.cc
index 74d473f4a125091038a48981037db56900676940..eb2d10b3f9d911b5d0fbd607766724d5fa203f8b 100644
--- a/src/platform-linux.cc
+++ b/src/platform-linux.cc
@@ -38,11 +38,6 @@
 #include <sys/types.h>
 #include <stdlib.h>
 
-#if defined(__GLIBC__) && !defined(__UCLIBC__)
-#include <execinfo.h>
-#include <cxxabi.h>
-#endif
-
 // Ubuntu Dapper requires memory pages to be marked as
 // executable. Otherwise, OS raises an exception when executing code
 // in that page.
@@ -66,7 +61,6 @@
 
 #include "v8.h"
 
-#include "platform-posix.h"
 #include "platform.h"
 #include "v8threads.h"
 #include "vm-state-inl.h"
@@ -154,14 +148,6 @@ void* OS::Allocate(const size_t requested,
 }
 
 
-void OS::DumpBacktrace() {
-  // backtrace is a glibc extension.
-#if defined(__GLIBC__) && !defined(__UCLIBC__)
-  POSIXBacktraceHelper<backtrace, backtrace_symbols>::DumpBacktrace();
-#endif
-}
-
-
 class PosixMemoryMappedFile : public OS::MemoryMappedFile {
  public:
   PosixMemoryMappedFile(FILE* file, void* memory, int size)