It's funny you should mention this- I'm struggling with this today,
in fact, for linux.

I've gotten somewhat along the way with this by snagging some
patches from ftp://atheist.tamu.edu/pub/richard/linux/axp.

In terms of netbsd the file

	ftp://ftp.netbsd.org/pub/NetBSD/arch/alpha/README.files

refers to another file

	ftp://ftp.netbsd.org/pub/NetBSD/arch/alpha/960615/src/cygnus.tar.gz

which purports to be the alpha/netbsd toolchain for the compiler tools.

I haven't unbundled it out myself, but I plan to do so sometime within
the next couple of days (I'm trying to compare the state of linux-alpha
&& netbsd-alpha, and the state of shared libraries is one of things I'm
interested in...although nominally I'm mostly a kernel weenie...)