In rcs 5.9.1 build-aux/extract-help is bash-specific

Hi,

in rcs 5.9.1 build-aux/extract-help uses a bash-specific construct, but has a sh hashbang.
The grep command may return 1 which aborts the execution of the script in sh, but not bash.
Forcing the returncode to true fixes the issue as in this patch:
  http://sourceforge.net/apps/trac/gar/browser/csw/mgar/pkg/rcs/trunk/files/0001-sh-bails-out-if-returncode-of-grep-is-1.patch?rev=22252

The issue occurred when compiling on Solaris 10 Sparc with Sun Studio 12.


Best regards

  -- Dago