Based on a patch from Jacek Caban.

usage:
     configure CFLAGS="-gdwarf-4 -O2"
   will enable dwarf4 compilation for ELF parts
   (and CROSSCFLAGS="-gdwarf-4 -O2" for PE parts)
Signed-off-by: Eric Pouech <eric.pouech@gmail.com>
Signed-off-by: Jacek Caban <jacek@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>