`cannot find -lreadline'

[Simon Marlow]

> Dear  ghc-5.02.2  (linux-i386-unknown, binary snapshot for libc-2.1),
> 
> For the program         main = putStr $ show $ (2+3 :: Int)
> 
>                         ghc --make Main
> `makes' it all right.
> And                     ghci -package docon Main
> also works.
> docon  is my user package, with  .hi files, .o, .a  libraries 
> gathered in certain directory. 
> 
> And                     ghc -package docon --make Main
> yields
>         ghc-5.02.2: chasing modules from: Main
>         Skipping  Main             ( Main.hs, ./Main.o )
>         ghc: linking ...
>         /usr/bin/ld: cannot find -lreadline
>         collect2: ld returned 1 exit status

Presumably, package 'docon' depends on package 'util', because package
'util' requires the readline library.  Linking against readline requires
libreadline.so, which is installed as part of the readline-devel package
on RedHat systems, and similarly on SuSE & Mandrake I think, but I'm not
sure about other Linux flavours.

If you install GHC from RPMs (the preferred option on systems that
support it), RPM will tell you about these dependencies.

Cheers,
	Simon