Add git-active utility

*** 193,202 ****
--- 193,205 ----
            sort > ~/unref-i386.out
          $ findunref $SPARCSRC $SPARCSRC/tools/findunref/exception_list | \
            sort > ~/unref-sparc.out
          $ comm -12 ~/unref-i386.out ~/unref-sparc.out > ~/unref.out
  
+ git-active
+         helper used by webrev to generate file lists for Git workspaces.
+ 
  hdrchk
          checks headers for compliance with OS/Net standards (form, includes,
          C++ guards).
  
  hgsetup