[Bug c/71613] Useful warnings silenced when macros from system headers are used

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71613

--- Comment #2 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
Really we need to review warnings and work out in each case what's right 
for macros from system headers.  If the issue is about the macro's 
contents, the warnings should be avoided; if it relates in some way to the 
context in which it is used, the warnings shouldn't be avoided.