The LAME install package on https://lame.buanzo.org/#lameosxdl does not work for me on MBP (early 2015) running OSX 10.3.3.
The install completes successfully, but libmp3lame.dylib is not created in /usr/local/lib/audacity.
The folder /usr/local/lib/audacity is not created and the dylib cannot be found anywhere under /usr/local/ or anywhere else on my MBP.
It took some Googling to discover the needed dylib file was simply in the ZIP download on the same page.
LAME on OSX ZIP version: