Merge remote-tracking branch 'origin/releases/gcc-11' into devel/omp/gcc-11

Merge up to r11-9011-g469aad8b5d787c728fbe8b4ec6537385d7815d5a (Sept 17, 2021).

diff --cc gcc/cp/decl.c
Simple merge

diff --cc gcc/doc/invoke.texi
Simple merge

diff --cc gcc/fortran/decl.c
Simple merge