uconv on Mac OS X anywhere?
My solution for you:

brew install icu4c

Read the message after install (nothing is at this moment direct available ...):


  ==> Caveats, 
  This formula is keg-only, which means it was not symlinked into /usr/local.


brew list icu4c | grep uconv


  /usr/local/Cellar/icu4c/55.1/bin/uconv
  
  /usr/local/Cellar/icu4c/55.1/share/man/man1/uconv.1


And after all, here my example for using this tool for normalization (NFC) utf8 text:

/usr/local/Cellar/icu4c/55.1/bin/uconv -f utf-8 -t utf-8 -x NFC ~/Desktop/ue.txt |  od -t x1