build breaks backwards compatibility

[dexterinbk]

In openexr-2.3.0, the libraries generated via the build script were easily found by imagemagick making this an easy delegate to enable. With 2.4.0, the face that cmake 3.10 is required, while only 2.8 is available on systems like amazonlinux, makes this library the most difficult to compile. If I run bootstrap, ./configure, make, make install now, the build has completed changed. It breaks backwards compatibility.