diff --git a/configure.in b/configure.in
index d1c39933a797..f97ba6faaebe 100644
--- a/configure.in
+++ b/configure.in
@@ -7310,6 +7310,10 @@ dnl ========================================================
 dnl C++ rtti
 dnl Should be smarter and check that the compiler does indeed have rtti
 dnl ========================================================
+if test -n "$GNU_CC"; then
+    _MOZ_USE_RTTI=1
+fi
+
 MOZ_ARG_ENABLE_BOOL(cpp-rtti,
 [  --enable-cpp-rtti       Enable C++ RTTI ],
 [ _MOZ_USE_RTTI=1 ],
diff --git a/ipc/chromium/chromium-config.mk b/ipc/chromium/chromium-config.mk
index 3f88202a179b..417f0acc8bd7 100644
--- a/ipc/chromium/chromium-config.mk
+++ b/ipc/chromium/chromium-config.mk
@@ -109,7 +109,3 @@ OS_CFLAGS += $(MOZ_GTK2_CFLAGS)
 
 endif # }
 endif # }
-
-ifdef OS_POSIX
-CXXFLAGS += $(MOZ_RTTI_FLAGS_ON)
-endif
diff --git a/ipc/chromium/src/build/build_config.h b/ipc/chromium/src/build/build_config.h
index a7f5ab80212f..66590447f7fa 100644
--- a/ipc/chromium/src/build/build_config.h
+++ b/ipc/chromium/src/build/build_config.h
@@ -76,19 +76,7 @@
 
 #else // CHROMIUM_MOZILLA_BUILD
 
-#if defined(OS_WIN)
-#define WCHAR_T_IS_UTF16
-#elif defined(OS_POSIX) && defined(COMPILER_GCC) && defined(__WCHAR_MAX__)
-#if (__WCHAR_MAX__ == 0x7fffffff || __WCHAR_MAX__ == 0xffffffff)
 #define WCHAR_T_IS_UTF32
-#elif (__WCHAR_MAX__ == 0x7fff || __WCHAR_MAX__ == 0xffff)
-#define WCHAR_T_IS_UTF16
-#endif
-#endif
-
-#if !defined(WCHAR_T_IS_UTF16) && !defined(WCHAR_T_IS_UTF32)
-#error Please add support for your compiler in build/build_config.h
-#endif
 
 #endif // CHROMIUM_MOZILLA_BUILD
 
diff --git a/toolkit/library/libxul-config.mk b/toolkit/library/libxul-config.mk
index 3ce7b552caf8..0d35c56c9caf 100644
--- a/toolkit/library/libxul-config.mk
+++ b/toolkit/library/libxul-config.mk
@@ -96,6 +96,8 @@ STATIC_LIBS += \
   mozipc_s \
   chromium_s \
   $(NULL)
+
+OS_LIBS += -lrt
 endif
 
 STATIC_LIBS += \