Log Message:
{,standalone-,static-}tcsh: Update to 6.23.01

Changes since 6.23.00:

  8. V6.23.01 - 20211209
  7. add \cc and \Uhhh, and document escape sequences
  6. add $'string with escapes' ("dollar-single-quotes") (Kimmo Suominen)
  5. don't glob the filetest builtin arguments twice
  4. remove the duplicate echo escape parsing code and use parseescape
  3. add \x{hh} \xhh \uhhh (H.Merijn Brand)
  2. fix and document ln=target
  1. Merge in patches from pkgsrc:
     - Modernize the installation targets so that they use INSTALL_DATA,
       INSTALL_PROGRAM, and MKDIR_P.
     - Enable SYSMALLOC and SHORT_STRINGS on NetBSD.
     - Enable NO_FIX_MALLOC and SHORT_STRINGS on OpenBSD.

For pkgsrc, items 1, 2, and 5 had already been applied via patches.