Add 'emptymatch', 'noemptymatch' options to regular expressions. * NEWS: Announce new options. * liboctave/regexp.cc (regexp::match): Add processing option for zero length matches. * liboctave/regexp.h (class opts): Add emptymatch option to constructors, setter/getter routines, private variable. * DLD-FUNCTIONS/regexp.cc (parse_options): Add emptymatch to options parsing routine. * DLD-FUNCTIONS/regexp.cc (octregexp): Ignore emptymatch when determing output ordering of arguments. * DLD-FUNCTIONS/regexp.cc (Fregexp): Add new options to docstring. Add %!tests for new behavior. * DLD-FUNCTIONS/regexp.cc (Fregexprep): Add %!tests for new behavior.

## The following libraries may be needed to satisfy gnulib dependencies:
##
##   $(COPYSIGN_LIBM)
##   $(FLOOR_LIBM)
##   $(GETHOSTNAME_LIB)
##   $(LIBSOCKET)
##   $(LIB_NANOSLEEP)
##   $(LTLIBINTL)
##   $(ROUNDF_LIBM)
##   $(ROUND_LIBM)
##   $(TRUNCF_LIBM)
##   $(TRUNC_LIBM)

LIBCRUFT_LINK_DEPS = \
  $(COPYSIGN_LIBM) \
  $(FLOOR_LIBM) \
  $(GETHOSTNAME_LIB) \
  $(LIBSOCKET) \
  $(LIB_NANOSLEEP) \
  $(LTLIBINTL) \
  $(ROUNDF_LIBM) \
  $(ROUND_LIBM) \
  $(TRUNCF_LIBM) \
  $(TRUNC_LIBM) \
  $(LAPACK_LIBS) \
  $(BLAS_LIBS) \
  $(FLIBS) \
  $(LIBS)

LIBCRUFT_LINK_OPTS =