diff --git a/mozilla/xpcom/base/nsStackFrameUnix.cpp b/mozilla/xpcom/base/nsStackFrameUnix.cpp
index 6899a44dbf0..b568ddfaeb2 100644
--- a/mozilla/xpcom/base/nsStackFrameUnix.cpp
+++ b/mozilla/xpcom/base/nsStackFrameUnix.cpp
@@ -83,7 +83,7 @@ void DemangleSymbol(const char * aSymbol,
 }
 
 
-#if defined(linux) && defined(__GNUC__) && (defined(__i386) || defined(PPC)) // i386 or PPC Linux stackwalking code
+#if defined(linux) && defined(__GNUC__) && (defined(__i386) || defined(PPC) || defined(__x86_64__)) // i386 or PPC Linux stackwalking code
 
 
 void DumpStackToFile(FILE* aStream)
diff --git a/mozilla/xpcom/base/nsTraceRefcntImpl.cpp b/mozilla/xpcom/base/nsTraceRefcntImpl.cpp
index 41011237f12..1e1852de4aa 100644
--- a/mozilla/xpcom/base/nsTraceRefcntImpl.cpp
+++ b/mozilla/xpcom/base/nsTraceRefcntImpl.cpp
@@ -816,7 +816,7 @@ nsTraceRefcntImpl::WalkTheStack(FILE* aStream)
 
 // WIN32 x86 stack walking code
 // i386 or PPC Linux stackwalking code or Solaris
-#elif (defined(linux) && defined(__GNUC__) && (defined(__i386) || defined(PPC))) || (defined(__sun) && (defined(__sparc) || defined(sparc) || defined(__i386) || defined(i386)))
+#elif (defined(linux) && defined(__GNUC__) && (defined(__i386) || defined(PPC) || defined(__x86_64__))) || (defined(__sun) && (defined(__sparc) || defined(sparc) || defined(__i386) || defined(i386)))
 #include "nsStackFrameUnix.h"
 NS_COM void
 nsTraceRefcntImpl::WalkTheStack(FILE* aStream)