This seems like it could break users. Can you add a #define to port.h instead, along the lines of the docs? https://github.com/google/glog#notes-for-windows-users

On second thoughts, as it's in copts rather than defines, it's unlike to affect users but it would still be cleaner to use the approach in the docs IMO.

Are you saying that the define is transitive, i.e., it is forwarded to library's consumer? Either way, CMake always defines GLOG_NO_ABBREVIATED_SEVERITIES on Windows to avoid conflicts due to ERROR:

If I recall correctly, on Windows glog without GLOG_NO_ABBREVIATED_SEVERITIES is unusable anyway once windows.h is included (which is in many cases true). Regardless, we should probably sync the approach taken by both build systems.

defines are transitive (useful when needed in public headers) but copts are not. If CMake does it too then this LGTM, thanks!