Hello Toby.
I also encountered this problem on OSX - for some reason Beanstalkd
will not build without the latest version of Make (3.81).
You can download the latest version and configure it with --path-
prefix=/usr/local prior to compiling so that it doesn't overwrite your
existing version of make.
Alternatively, you can try install gmake using Darwin Ports which
should be the correct version.
Also remember, if you have libevent installed via Darwin Ports, you
need to tell make where to find it:
export C_INCLUDE_PATH=/opt/local/include
export LIBRARY_PATH=/opt/local/lib
HTH
Luke