configure scripts contain bashisms

[atsampson]

The bootstrap and configure scripts for ilmbase and openexr 2.2.0 make use of some non-standard shell features, so they work on a system where /bin/sh is bash, but not elsewhere. Most of these are test x == y where test x = y is intended; there's also one use of ${..//..} and one of arrays in ilmbase's "multiple OS X architectures" test.

The fixes are trivial: here's a patch for ilmbase and a patch for openexr.