I've built both a 32-bit and 64-bit versions. Here is an updated summary of my experience building Ipopt 3.10.3 and the Matlab interface for it on Mac OS X 10.8 Mountain Lion using the MUMPS linear solver and the native OS X BLAS/LAPACK. (See an older version of this page for details on building Ipopt on Snow Leopard 10.6 or Lion 10.7, or with other linear solvers or BLAS/LAPACK options.)
Ipopt and the Matlab Interface on Mac OS Xīy Ray Zimmerman, (last updated May 2, 2013)