Handle .debug_macro in debugedit.
    
    When compiling with -g3 gcc will generate a .debug_macro section
    which has pointers to the .debug_str section. Since we might rewrite
    the .debug_str section, we also need to update any .debug_macro
    pointers.
    
    Updated the debugedit.at testcase by building everything with -g
    and add various checks to see the .debug_macro section looks OK
    after running debugedit. Added a new rpmbuild.at testcase to check
    handing of .debug_macro in the whole rpmbuild debuginfo pipeline
    to double check the separate .debug file also contains the macros.
    
    Original patch by Michael Schroeder <mls@suse.de>. Extended by
    Mark Wielaard <mark@klomp.org> to deal with relocations and possible
    multiple COMDAT .debug_macro sections.