[Bug c/81404] New: suggested hints for standard C macros should avoid GCC predefined macros

["msebor at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81404

            Bug ID: 81404
           Summary: suggested hints for standard C macros should avoid GCC
                    predefined macros
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: msebor at gcc dot gnu.org
  Target Milestone: ---

The fix-it hints printed along with errors for standard C library macros like
INT_MAX suggest GCC predefined symbols like __INT_MAX__ over the standard
symbols.  They should suggest the latter (along with the header the symbol is
defined in).

$ cat a.c && gcc -S -Wall a.c
int i = INT_MAX;
a.c:1:9: error: ‘INT_MAX’ undeclared here (not in a function); did you mean
‘__INT_MAX__’?
 int i = INT_MAX;
         ^~~~~~~
         __INT_MAX__