Upstream commit: 2585d7b839559e665d5723734862fbe62264b25d
- Do not use generic selection in C++ mode
- Do not use __builtin_types_compatible_p in C++ mode (#1481205)
- x86-64: Check FMA_Usable in ifunc-mathvec-avx2.h (swbz#21966)
- Various locale fixes (swbz#21750, swbz#21960, swbz#21959, swbz#19852)
- Fix sigval namespace (swbz#21944)
- x86-64: Optimize e_expf with FMA (swbz#21912)
- Adjust glibc-rh827510.patch.