New Issue: problem with struct-fn-ptr test with GCC 9

16256, “mppf”, “problem with struct-fn-ptr test with GCC 9”, “2020-08-19T17:05:53Z”

In creating PR #16187 I noticed that the future extern/ferguson/externblock/struct-fn-ptr seems to depend on the GCC version. It fails with GCC 9 but passes with GCC 8. The issue is related to PR #14446. GCC 9 mentions -Werror=discarded-qualifiers and adding the corresponding -Wno-error=discarded-qualifiers makes the error go away in GCC 9.

Should we add -Wno-error=discarded-qualifiers to the make/compiler/Makefile.gnu?