I'm building a package which relies on readline 5.1, however
I installed readline 5.1 to /opt/readline-5.1/ and i have it in my ld.conf file as /opt/readline/lib and it's not checking.
How do i make a configure script search for non-standard directories?
(I have multiple versions of readline installed so they won't conflict with each other and so I won't make as much of a mess.



configure: error: CGDB requires GNU readline 5.1 or greater to link.
If you used --with-readline instead of using the system readline library,
make sure to set the correct readline library on the linker search path
via LD_LIBRARY_PATH or some other facility.

Probably with

Why did you install readline to /opt just out of curiosity? That's a pretty standard package. It also comes with slack...

Any configure questions and you should consult

for the answer. Also, I'm sure you updated "ldconfig" as well? Just checking...

I installed readline to opt because I didn't want to replace the one that came with slackware and the code i'm compilng depends on a later version.

Pass it like this:
LD_LIBRARY_PATH=/opt/readline/lib:$PATH ./configure prefix=/whatever

Do the same for compiling also.

Is there a way I can make those settings permanant?

ldconfig does that through your ld.so.conf file. But not all configure scripts and Makefiles will correctly find them, which is why it works if you do it as above.
BTW, the order in which you put the entries in the conf file will probably affect which libs get used by a program, if there are more than one version of the same lib.
You can always make a wrapper for running the program which sets up the environment before running the prog:

#/bin/bash
LD_LIBRARY_PATH=/opt/readline/lib:$PATH
exec /path/to/prog "$@"
exit 0

Name it whatever and place in your path.

You don't need to do any of this. There's a readline 5.1 package on linuxpackages.net. Just download it and install it with upgradepkg.

Another option is to use the readline SlackBuild script from either slackware 10.2 or slackware-current to compile readline 5.1 into a package that you then install with upgradepkg.

Either option will upgrade your system's readline package to 5.1.

That's all you need to do.

If the new readline gives your problems (it won't), then you can instantly switch back to the old version by using upgradepkg on the readline package that comes with the distribution.

I understand you're probably worried that your existing packages might depend on the older version of readline and stop working if you replace it with the newer version. Don't worry about that; Slackware doesn't work that way.