[igraph] compilation on Mac OS X

[Mark McClure]

I have several attempting to compile the igraph C library
on Mac OS X 10.6.2 (the new Snow Leopard) on my brand new
64 bit MacBook Pro.

First, when I run ./configure, the script ultimately responds
that igraph was successfully configured with some specific
information such as:
  GraphML format support -- no
  GMP library support    -- yes
Thus, I expect to be able to build the library with GMP
support but I receive the following error after make:
ld: pointer in read-only segment not allowed in slidable image,
used in ___gmpn_divexact_1 from /usr/local/lib/libgmp.a(dive_1.o)
collect2: ld returned 1 exit status
make[3]: *** [libigraph.la] Error 1

I was able to build the library after disabling GMP but it
would be nice to have it.  Also, I don't understand why
GraphML support is turned off since libxml2 is supposedly
included with this version of OS X.  Indeed, the libxml2
libraries seem to be installed in /usr/lib:
mcmcclur$ ls /usr/lib | grep xml
libxml2.2.7.3.dylib
libxml2.2.dylib
libxml2.dylib
xml2Conf.sh

Perhaps the configure script is not looking in the
appropriate place?

Finally, I'd love to be able to build my application to
run on several versions of OS X but the configure script
doesn't recognize the command line arguments to allow
this.  in particular, I'd like to be able to specify
extra compiler flags like so:
./configure CFLAGS=-arch i386 -arch x86_64 -mmacosx-version-min=10.4

Is that the correct syntax?  Or do I need quotes?
And how should the configure script be edited to accept
these flags?

Thanks,
Mark McClure