build: Use bison at build time rather than lexyacc.sh to build the embedded heimdal

build: Use bison at build time rather than lexyacc.sh to build the embedded heimdal

Because the filenames are changed to the *.tab.{h,c} format
a transitional header is added.

While the built compilers differ, the output of the compilers
and the resulting .o files have been verified not to have changed
on Ubuntu 20.04.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>