show the revision of files in the bulk logs

[Roland Illig <roland.illig%gmx.de@localhost>]

Hi all,

when bug-hunting bulk-build packages, I would like to know the exact 
version of the files involved in the build process. The appended patch 
adds a show-ident target to show the ident strings of some files.

The bulk-build should run

    ${MAKE} ${MAKEFLAGS} show-idents

before actually doing the package (around line 384).

Roland