darwin/clang libtool (was: No dynamic libraries on Mac OS X)

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

I think the problem is something different.

Let's put aside the question why readline doesn't install dylibs if libtools 
happens to think my fortran linker can't deal with dylibs (what about 
Plankalkül and 6502 Assembler?).

The relevant part of libtool's configure script looks like this:

  lt_save_GCC=$GCC
[...]
  GCC=$G77
[...]

  ld_shlibs_F77=yes
  if test "$with_gnu_ld" = yes; then
[...]
  else
    # PORTME fill in a description of your system's linker (not GNU ld)
    case $host_os in
[...]
    darwin* | rhapsody*)
[...]
  case $cc_basename in
     ifort*) _lt_dar_can_shared=yes ;;
     *) _lt_dar_can_shared=$GCC ;;
  esac
  if test "$_lt_dar_can_shared" = "yes"; then
[...]
  else
  ld_shlibs_F77=no
  fi
      ;;

So the logic seems to be that on darwin with a non-GNU linker, Fortran can deal 
with sharerd libraries iff it's either ifort* (whatver that is) or g77.

I think the test should at least add a case for f2c and then set ld_shlibs_F77 
to ld_shlibs (meaning C shared library support).