b5a8055b5c
This is a change done upstream in the `devel3` branch for 3.13.6: https://github.com/embree/embree/commit/82ca6b5ccb7abe0403a658a0e079926478f04cb1 They also seem to define it for macOS, but for us it breaks the build... ¯\_(ツ)_/¯ Also change wrong use of CPPFLAGS (pre-processor) where CXXFLAGS (C++) makes more sense.