There seems to be something broken in the latest version of Julia on OSX. I believe the bug is in libunwind, due to it referencing ucontext.h:
make cleanall
make
...snip...
/bin/sh ../libtool --mode=install /usr/local/bin/ginstall -c dnsimp '/Users/tom/Source/julia/usr/bin'
libtool: install: /usr/local/bin/ginstall -c .libs/dnsimp /Users/tom/Source/julia/usr/bin/dnsimp
CC src/jltypes.o
In file included from jltypes.c:13:
In file included from ./julia.h:1228: