Readline on netbsd should use posix ttys

[Ian Dall]

Gdb 4.16.97 for netbsd hosts can cause a garbled screen. This happens
when a terminal and serial port is set to 8 bits no parity. When gdb
runs it changes the setting to be incompatible with the terminal.

I don't know if this is due to a bug in netbsd's emulation of the
"new" tty discipline, but in anycase, posix ttys are preferred on
NetBSD and probably other modern BSD derivatives. The problem goes away
if the readline library is compiled with -D_POSIX_VERSION.

The diffs (attached) are trivial.

Ian

*** ../gdb-4.16.97/readline/configure.in	Fri Aug 30 06:58:02 1996
--- readline/configure.in	Tue Apr  7 22:50:51 1998
***************
*** 50,55 ****
--- 50,56 ----
    *-*-sunos4.1*)	host_makefile_frag=config/mh-posix ;;
    *-*-ultrix2*)						files=sysdep-obsd.h ;;
    *-*-riscos*)		host_makefile_frag=config/mh-sysv ;;
+   *-*-netbsd*)		host_makefile_frag=config/mh-bsd44 ;;
  esac
  
  # per-target:
diff -c -P ../gdb-4.16.97/readline/config/mh-bsd44 readline/config/mh-bsd44
*** ../gdb-4.16.97/readline/config/mh-bsd44	Thu Jan  1 09:30:00 1970
--- readline/config/mh-bsd44	Tue Apr  7 22:51:18 1998
***************
*** 0 ****
--- 1,2 ----
+ # Define USG as -DUSG if you are using a System V operating system.
+ USG = -D_POSIX_VERSION