Nest-var, OMP_NESTED, omp_set_nested()., and omp_get_nested() have been deprecated in the 5.0 spec. Initial nesting info is now derived from OMP_MAX_ACTIVE_LEVELS, OMP_NUM_THREADS, and OMP_PROC_BIND.
This patch deprecates the internal ICV that corresponds to nest-var, and replaces it with the max-active-levels-var ICV to determine nesting. The change still allows for use of OMP_NESTED (according to 5.0 changes), omp_get_nested, and omp_set_nested, which have had deprecation messages added to them. The change allows certain settings of OMP_NUM_THREADS, OMP_PROC_BIND, and OMP_MAX_ACTIVE_LEVELS to turn on nesting, but OMP_NESTED=0 will still force nesting to be off.
The runtime now prints informative messages about deprecation of OMP_NESTED, omp_set_nested(), and omp_get_nested(), when those environment variables or routines are used. It also prints deprecated message in output for KMP_SETTINGS and OMP_DISPLAY_ENV for OMP_NESTED. This patch also fixes OMP_DISPLAY_ENV output for OMP_TARGET_OFFLOAD.