maint: Rename regexp.h to lo-regexp.h, regexp.cc to lo-regexp.cc in liboctave. Remove namespace hit with regexp.cc in libinterp/corefcn. * liboctave/util/lo-regexp.cc: Renamed from regexp.cc. * liboctave/util/lo-regexp.h: Renamed from regexp.h. * liboctave/util/module.mk: Add files to build system. * libinterp/corefcn/regexp.cc, libinterp/corefcn/symtab.h, libinterp/corefcn/variables.cc: Update #include stmts to new name.

#!/bin/sh
#
# Like mv $1 $2, but if the files are the same, just delete $1.
# Status is 0 if $2 is changed, 1 otherwise.

if test -r $2; then
  if cmp $1 $2 > /dev/null; then
    echo $2 is unchanged
    rm -f $1
  else
    mv -f $1 $2
  fi
else
  mv -f $1 $2
fi