ims_dialog: remove execinfo usage
Currently, ims_dialog includes execinfo.h to use backtrace in the
backtrace2str function. However, all calls to backtrace2str are
commented so disable this function through "if 0" and comment the
include on execinfo.h to allow the cross-compilation of the ims_dialog
module as some libc's don't always have this header (uclibc-ng, musl)
Signed-off-by: Fabrice Fontaine <[email protected]>