[Haskell-cafe] Re: Installing Haskell on OSX

[Sudish Joseph]

Antoine Latter <aslatter at gmail.com> writes:
> On Sun, Jun 20, 2010 at 12:53 PM, Giuseppe Luigi Punzi Ruiz
> <glpunzi at lordzealon.com> wrote:
>> Hi again,
>>
>> Yes, you are right, but now, "cabal install leksah" I get:
>>

[...]

>> Undefined symbols:
>>  "_iconv_close", referenced from:
>>      _hs_iconv_close in libHSbase-4.2.0.0.a(iconv.o)
>>  "_iconv_open", referenced from:
>>      _hs_iconv_open in libHSbase-4.2.0.0.a(iconv.o)
>>  "_iconv", referenced from:
>>      _hs_iconv in libHSbase-4.2.0.0.a(iconv.o)
>> ld: symbol(s) not found

> This one is a bummer, and I see it all the time when I try to build a
> package linked against macports.

This is caused by the two libiconv's in the system being
ABI-incompatible, sadly.  The ghc pkg available for download from
haskell.org is linked against the system /usr/lib/libiconv.dynlib, which
has iconv_open() as a function.  Macports has GNU libiconv which
#defines iconv_open to libiconv_open() in /opt/local/include/iconv.h.

This then blows up as above when linking against other libraries in
macports - the linker pulls in GNU libiconv which lacks the symbols
needed as you see above.

One workaround is to link GHC itself against the macports version of
libiconv (and libgmp) and have cabal-install link all subsequent
libraries against macports.  I did just that this weekend and now have a
working threadscope using the Quartz backend for gtk2, which is very
nice (no need to run the X server).

Recipe for reproducing this build is included below (and I can also
provide the resulting ghc-6.12.3 pkg file if needed).

Another possible option is to use Homebrew to install gtk2 and other
dependencies.  Homebrew prefers to use the system-provided libraries and
will not pull in GNU libiconv, so this should work with the existing GHC
pkg in theory.  I didn't pursue this since the homebrew 'gtk+' package
didn't seem to have the option to use Quartz instead of X11 as its
backend.

Steps for linking the ghc runtime against macports:

-  Specify EXTRA_CABAL_CONFIGURE_FLAGS in mk/build.mk as mentioned at
   the bottom of http://www.haskell.org/ghc/download_ghc_6_12_3.html

   EXTRA_CABAL_CONFIGURE_FLAGS = --extra-include-dirs=/opt/local/include \
                                 --extra-lib-dirs=/opt/local/lib

-  Use the --with-iconv-* and --with-gmp-* flags when configuring ghc.

   ./configure --with-iconv-includes=/opt/local/include \
               --with-iconv-libraries=/opt/local/lib \
               --with-gmp-includes=/opt/local/include \
               --with-gmp-libraries=/opt/local/lib

-  This produces a GHC runtime and libraries linked against macports:

   % otool -L ghc
   ghc:
	/opt/local/lib/libncurses.5.dylib (compatibility version 5.0.0, current version 5.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.0)
	/opt/local/lib/libiconv.2.dylib (compatibility version 8.0.0, current version 8.0.0)
	/opt/local/lib/libgmp.10.dylib (compatibility version 11.0.0, current version 11.1.0)

   % nm HSbase-4.2.0.2.o | fgrep iconv
   001ff7f0 T _hs_iconv
   001ff7e0 T _hs_iconv_close
   001ff800 T _hs_iconv_open
            U _libiconv
            U _libiconv_close
            U _libiconv_open

   ghc and included libraries use the macports libiconv, so linking
   against other libraries in macports (gtk2!) will work.

-  Have cabal-install use macports as well for packages it installs by
   editing ~/.cabal/config and setting:

   extra-include-dirs: /opt/local/include
   extra-lib-dirs: /opt/local/lib

-  This gives, for e.g., threadscope linked against macports:

   % otool -L ~/.cabal/bin/threadscope | egrep '(gtk|iconv)'
	/opt/local/lib/libgtk-quartz-2.0.0.dylib (compatibility version 2001.0.0, current version 2001.1.0)
	/opt/local/lib/libiconv.2.dylib (compatibility version 8.0.0, current version 8.0.0)

-  Note that since the ghc runtime is still in 32-bit i386 mode, we
   need universal versions of most libraries in macports.  Recent
   versions of macports (1.9 for sure, maybe 1.8) make it simple to
   switch from an x86_64 library to a universal one:

   % port install gtk2 +universal

   This will recompile gtk2 and *all* dependent libraries as universal
   libraries which is exactly what you need.  You can then eliminate any
   inactive 64-bit libraries with:

   % port -f uninstall inactive

> Here's the last thread about with, with more links and discussion:
>
> http://thread.gmane.org/gmane.comp.lang.haskell.general/18064/
>
> The response by Jean-Marie Gaillourdet has worked for me in the past.
>
> Antoine

Thanks for that link, I didn't think of overriding libiconv on a
per-package basis.

-Sudish