Return int, not void, to conform with the expected arg of tputs.
* readline.c (init_terminal_io): tgetflag only takes 1 arg.
* readline.c (_rl_savestring): New function.
* chardefs.h: To avoid conflicts and/or warnings, define
savestring as a macro wrapper for _rl_savestring.
* display.c (extern term_xn): It's an int flag, not a string.
* charsdefs.h, rldefs.h: Remove HAVE_STRING_H-related junk.
that the file readline.c has been split into multiple files.
* bind.c, complete.c, dispay.c, isearch.c, parens.c, rldefs.h,
rltty.c, search.c signals.c, tilde.c, tilde.h, xmalloc.c: New files.
