Need help with autoconf configure script

[Bob Rossi]

Hi again,

I'm still trying to get CGDB working with autoconf. I've got a very
strange problem. I have this in my configure.in,

   if test "$opt_with_readline_prefix" = "no"; then
   echo "READLINE_PREFIX=NO"
   else
   echo "READLINE_PREFIX=YES"
   VL_LIB_READLINE
   fi

I downloaded VL_LIB_READLINE from here,
  http://autoconf-archive.cryp.to/vl_lib_readline.html
although I have modified it slightly (see attachment).

If I run ./configure then by default opt_with_readline_prefix is "no".
During ../cgdb/configure I get,
   checking pty.h usability... yes
   checking pty.h presence... no
   configure: WARNING: pty.h: accepted by the compiler, rejected by the 
preprocessor!
   configure: WARNING: pty.h: proceeding with the compiler's result
   checking for pty.h... yes
so I get error's when VL_LIB_READLINE is *not* run.

If I run ../cgdb/configure --with-readline, then
opt_with_readline_prefix is not "no". This causes VL_LIB_READLINE to
run. When this happens, I get,

   checking pty.h usability... yes
   checking pty.h presence... yes
   checking for pty.h... yes

I can't figure out why I'm getting error's when VL_LIB_READLINE is not
run. Any help would be greatly appreciated. I've attached the slightly
modified version of VL_LIB_READLINE that I am using.

Thanks,
Bob Rossi

readline.m4
Description: Text document