Add -fno-global-ctor-const-promotion option.

The global variable optimization pass of LLVM will try to
evalutate the global variables with static constructors, and
promote the global constants.  Although this optimization is
correct, it may cause some incompatability between gcc in
some incorrect code, which uses const_cast to cast the
constant to mutable.  If you are compiling the legacy code,
then you can try to add -fno-global-ctor-const-promotion
to your CXXFLAGS.

Change-Id: I24bae9f0bc82fbede0be35087ff5336eed300e5d