Compiling gnu utilities on MacOSX

As someone had pointed out, I was using a gnu sed when modifying the make file for libgsm.
MacOSX does not ship with a gnu sed.

This is how I usually build gnu utilities (and basically, everything else I need and build from source)

As an example, how to build sed is shown:

First, obtain and unpack sed

$ /usr/bin/curl -O
$ tar xzpf sed-4.1.5

Set up compiler flags

$ export CFLAGS="-isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch x86_64 -arch ppc64 -arch ppc -arch i386 -arch x86_64 -mmacosx-version-min=10.4"
$ export LDFLAGS="-Wl,-syslibroot,/Developer/SDKs/MacOSX10.4u.sdk -arch x86_64 -arch ppc64 -arch ppc -arch i386 -mmacosx-version-min=10.4"

Start the compilation and install