diff -up xulrunner-9.0/mozilla-beta/ipc/chromium/src/base/data_pack.cc.secondary-ipc xulrunner-9.0/mozilla-beta/ipc/chromium/src/base/data_pack.cc
--- xulrunner-9.0/mozilla-beta/ipc/chromium/src/base/data_pack.cc.secondary-ipc	2011-12-07 07:27:43.000000000 +0100
+++ xulrunner-9.0/mozilla-beta/ipc/chromium/src/base/data_pack.cc	2011-12-09 14:35:50.397220865 +0100
@@ -91,14 +91,7 @@ bool DataPack::Load(const FilePath& path
 bool DataPack::Get(uint32_t resource_id, StringPiece* data) {
   // It won't be hard to make this endian-agnostic, but it's not worth
   // bothering to do right now.
-#if defined(__BYTE_ORDER)
-  // Linux check
-  COMPILE_ASSERT(__BYTE_ORDER == __LITTLE_ENDIAN,
-                 datapack_assumes_little_endian);
-#elif defined(__BIG_ENDIAN__)
-  // Mac check
-  #error DataPack assumes little endian
-#endif
+#warning DoTheRightThingMakingThisEndianAgnostic!
 
   DataPackEntry* target = reinterpret_cast<DataPackEntry*>(
       bsearch(&resource_id, mmap_->data() + kHeaderLength, resource_count_,
diff -up xulrunner-9.0/mozilla-beta/ipc/chromium/src/build/build_config.h.secondary-ipc xulrunner-9.0/mozilla-beta/ipc/chromium/src/build/build_config.h
--- xulrunner-9.0/mozilla-beta/ipc/chromium/src/build/build_config.h.secondary-ipc	2011-12-07 07:27:43.000000000 +0100
+++ xulrunner-9.0/mozilla-beta/ipc/chromium/src/build/build_config.h	2011-12-09 14:39:44.922231601 +0100
@@ -59,11 +59,23 @@
 #define ARCH_CPU_ARMEL 1
 #define ARCH_CPU_32_BITS 1
 #define WCHAR_T_IS_UNSIGNED 1
+#elif defined(__powerpc64__)
+#define ARCH_CPU_PPC64 1
+#define ARCH_CPU_64_BITS 1
 #elif defined(__ppc__) || defined(__powerpc__)
 #define ARCH_CPU_PPC 1
 #define ARCH_CPU_32_BITS 1
-#elif defined(__sparc64__)
+#elif defined(__s390x__)
+#define ARCH_CPU_S390X 1
+#define ARCH_CPU_64_BITS 1
+#elif defined(__s390__)
+#define ARCH_CPU_S390 1
+#define ARCH_CPU_32_BITS 1
+#elif defined(__sparc__) && !defined(__arch64)
 #define ARCH_CPU_SPARC 1
+#define ARCH_CPU_32_BITS 1
+#elif defined(__sparc__) && defined(__arch64)
+#define ARCH_CPU_SPARC64 1
 #define ARCH_CPU_64_BITS 1
 #else
 #error Please add support for your architecture in build/build_config.h
diff -up xulrunner-9.0/mozilla-beta/ipc/chromium/src/chrome/common/ipc_message_utils.h.secondary-ipc xulrunner-9.0/mozilla-beta/ipc/chromium/src/chrome/common/ipc_message_utils.h
--- xulrunner-9.0/mozilla-beta/ipc/chromium/src/chrome/common/ipc_message_utils.h.secondary-ipc	2011-12-07 07:27:43.000000000 +0100
+++ xulrunner-9.0/mozilla-beta/ipc/chromium/src/chrome/common/ipc_message_utils.h	2011-12-09 14:40:59.602679278 +0100
@@ -195,7 +195,8 @@ struct ParamTraits<unsigned long long> {
 };
 #endif
 
-#if !(defined(OS_MACOSX) || defined(OS_OPENBSD) || defined(OS_WIN) || (defined(OS_LINUX) && defined(ARCH_CPU_64_BITS)))
+// Although s390 is a 32-bit system it defines size_t as unsigned long
+#if !(defined(OS_MACOSX) || defined(OS_OPENBSD) || defined(OS_WIN) || (defined(OS_LINUX) && (defined(ARCH_CPU_64_BITS) || defined(ARCH_CPU_S390))))
 // There size_t is a synonym for |unsigned long| ...
 template <>
 struct ParamTraits<size_t> {