The solution for compiling Gretl on Snow Leopard is as follows:
1. delete all .la files in the GTK+.framework
Needed since Apple has removed many/all .la files from /usr./lib
2. define CC="gcc -arch i386" for configure.
This is absolutely required since on Snow Leopard the default is 64
And everything compiled must be 32 bits for Gretl to work.
The CC define is the only way to get consistent 32bits compile and
There is no need to modify anything in the source tarball.
I got this from a message from Urbanek to the R-SIG_Mac mailing list.