openexr

When compiling master & RB-2.4 with Visual Studio 17, there are lot of warnings. Most of them only require a small change in the source code. But one require several iterations to be correctly fixed in OCIO.

F:\OpenSource\openexr\IlmBase\Iex\IexBaseExc.cpp(393): warning C4996: 'getenv': This function or variable may be unsafe. Consider using _dupenv_s instead. To disable deprecation,

Sometimes it is very handy to have a "Rule of Thirds" overlay:

testMatrix() in testExtractSHRT.cpp fails to check the return status of extractSHRT(). If the input matrix is invalid, it will produce garbage results. A better solution is to assert that extractSHRT() returns true.

Adding this assert will eliminate an uninitialized variable reference warning, since the s, h, r, and t variables may be unset.