diff -r 000000000000 -r 6474c204b198 build/unix/mozconfig.linux
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/build/unix/mozconfig.linux	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,28 @@
+if [ "x$IS_NIGHTLY" = "xyes" ]; then
+  MOZ_AUTOMATION_UPLOAD_SYMBOLS=1
+  MOZ_AUTOMATION_UPDATE_PACKAGING=1
+fi
+
+. "$topsrcdir/build/mozconfig.common"
+
+# some b2g desktop builds still happen on i686 machines, and the tooltool
+# toolchain is x86_64 only.
+# We also deal with valgrind builds here, they don't use tooltool manifests at
+# all yet.
+if [ -z "$no_tooltool" ]
+then
+  CC="$topsrcdir/gcc/bin/gcc"
+  CXX="$topsrcdir/gcc/bin/g++"
+
+  # We want to make sure we use binutils and other binaries in the tooltool
+  # package.
+  mk_add_options PATH="$topsrcdir/gcc/bin:$PATH"
+else
+  CC="/tools/gcc-4.7.3-0moz1/bin/gcc"
+  CXX="/tools/gcc-4.7.3-0moz1/bin/g++"
+fi
+
+ac_add_options --enable-elf-hack
+
+# Avoid dependency on libstdc++ 4.7
+ac_add_options --enable-stdcxx-compat