[Bug c/66938] New: using bool as destination in overflow checkers

["rv at rasmusvillemoes dot dk" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66938

            Bug ID: 66938
           Summary: using bool as destination in overflow checkers
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Severity: trivial
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rv at rasmusvillemoes dot dk
  Target Milestone: ---

Playing around with the __builtin_*_overflow checkers, I noticed that when the
third argument is pointer to _Bool one gets "error: argument 3 in call to
function '__builtin_add_overflow' does not have pointer to integer type".
Technically, _Bool _is_ an integer type.

I can't really think of a situation where one would want to do arithmetic on
_Bools, or to know if the result of a computation is 0 or 1, so this is mostly
about the wording of the error message [also, "does not have" should probably
be "is not"]. But maybe adding support for _Bools is easy enough to just do it
for completeness.