Fix C4266 warning

Author: walbourn

Auxiliary/DirectXTexEXR.cpp

@@ -45,8 +45,13 @@
 #pragma warning(disable : 4244 4996)
 #include <ImfRgbaFile.h>
 #include <ImfIO.h>
+
+// https://openexr.com/en/latest/PortingGuide.html
+#include <OpenEXRConfig.h>
 #pragma warning(pop)
 
+#define COMBINED_OPENEXR_VERSION ((10000*OPENEXR_VERSION_MAJOR) + (100*OPENEXR_VERSION_MINOR) +  OPENEXR_VERSION_PATCH)
+
 #ifdef __clang__
 #pragma clang diagnostic pop
 #endif
@@ -148,6 +153,13 @@ namespace
             SetLastError(0);
         }
 
+#if COMBINED_OPENEXR_VERSION >= 30300
+        int64_t read(void *buf, uint64_t sz, uint64_t offset) override
+        {
+            return Imf::IStream::read(buf, sz, offset);
+        }
+#endif
+
     private:
         HANDLE m_hFile;
         LONGLONG m_EOF;