[og11][committed] openmp: Improve handling of nested OpenMP metadirectives in C and C++

[Kwok Cheung Yeung]

This patch has been committed to the devel/omp/gcc-11 development branch:
249df772b70f7b9f50f68030d4ea9c25624cc578  openmp: Improve handling of 
nested OpenMP metadirectives in C and C++

Kwok