I followed the instructions for OS X:
brew install icu4c
ln -s /usr/local/Cellar/icu4c/51.1/include/unicode /usr/local/include
ln -s /usr/local/Cellar/icu4c/51.1/bin/icu-config /usr/local/bin/icu-config
npm install node-stringprep
But still I get the "Symbol node_stringprep_module not found" error as in issue #27. I have node v0.10.5.
(I also tried rebuilding node-stringprep after linking to icu4c/49.1.2 as I see there is some vague issue with recent versions?)