Mono 2.4.6 configure scripts generates 32 bit build and requires 32 bit dependencies.
This is a problem in Snow Leopard which is all 64 bit. I had to use the following settings.
export CFLAGS="-I/Users/amitava/local/include -arch i386 -m32"
Please note that we have to override the system defaults by the generated packages. So I append $prefix (/Users/amitava/local in my case) to the PATH environment variable
The following packages were needed
And to build mono
./configure --prefix=$HOME/local --with-tls=pthread