While I don't write and don't like C++, I don't understand why major foss projects choosing clang over gcc due to a philosophical spat is anything other than damning.
gcc should be fighting hard to continue to provide features competitive to clang while remaining true to it's values, but instead it has opted out of this for hypothetical purity (exporting the data in question is within the license terms and does not require changes in gcc itself, it can be implemented as a plugin, rms just doesn't like it and discourages loudly its implementation as it simply makes it easier for proprietary tools to use it. The situation is quite similar to dynamic linking).
gcc should be fighting hard to continue to provide features competitive to clang while remaining true to it's values, but instead it has opted out of this for hypothetical purity (exporting the data in question is within the license terms and does not require changes in gcc itself, it can be implemented as a plugin, rms just doesn't like it and discourages loudly its implementation as it simply makes it easier for proprietary tools to use it. The situation is quite similar to dynamic linking).