Add support for .deb files to abipkgdiff

Add support for .deb files to abipkgdiff

This lets abipkgdiff compare debian binary packages.

The patch contains test cases for debian package with split debug info
that is referenced by the build-id scheme.  These test cases come from
the bug report https://sourceware.org/bugzilla/show_bug.cgi?id=18792,
more particularly from the attachment
https://sourceware.org/bugzilla/attachment.cgi?id=8516.

	* include/abg-tools-utils.h (file_type): Add FILE_TYPE_DEB.
	* tools/abipkgdiff.cc (extract_deb): New.
	(extract_package, main): Handle FILE_TYPE_DEB.
	* src/abg-tools-utils.cc (operator<<): Handle FILE_TYPE_DEB.
	(guess_file_type): Detect FILE_TYPE_DEB.
	* tools/abidiff.cc (main): Handle FILE_TYPE_DEB.
	* tools/abilint.cc (main): Handle FILE_TYPE_DEB.
	* tests/data/test-diff-pkg/libsigc++-2.0-0c2a-dbgsym_2.4.0-1_amd64.ddeb:
	Input debian debug info package; to be compared by the test
	harness runtestdiffpkg.
	* tests/data/test-diff-pkg/libsigc++-2.0-0c2a_2.4.0-1_amd64.deb:
	Input debian package; to be compared by the test harness
	runtestdiffpkg.
	* tests/data/test-diff-pkg/libsigc++-2.0-0v5-dbgsym_2.4.1-1ubuntu2_amd64.ddeb:
	Input debug info package
	* tests/data/test-diff-pkg/libsigc++-2.0-0v5_2.4.1-1ubuntu2_amd64.deb:
	Input debian package; to be compared by the test harness
	runtestdiffpkg.
	* tests/data/test-diff-pkg/libsigc++-2.0-0c2a_2.4.0-1_amd64--libsigc++-2.0-0v5_2.4.1-1ubuntu2_amd64-report-0.txt:
	Reference output for the comparison of the packages above.
	* tests/data/Makefile.am: Add the new files above to the source distribution.
	* tests/test-diff-pkg.cc (in_out_specs): Add the input packages
	above to the set of files to be compared by this test harness.

Signed-off-by: Matthias Klose <doko@debian.org>
Signed-off-by: Dodji Seketeli <dodji@redhat.com>