[Bug c++/66231] New: -Werror=zero-as-null-pointer-constant - errors on -isystem function default values of NULL

[darlingm at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66231

            Bug ID: 66231
           Summary: -Werror=zero-as-null-pointer-constant - errors on
                    -isystem function default values of NULL
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: darlingm at gmail dot com
  Target Milestone: ---

I'm using -Werror=zero-as-null-pointer-constant.

I'm using a library with a header providing default values on some functions of
NULL.

gcc trunk issues an error, since I'm using that default value.

But, I included that library's headers with -isystem.

I get that in one sense NULL is "imported" into my source and used, but I
really think the spirit of -isystem is being violated here.  I either have to
edit library header files which aren't mine, or I can't use
-Werror=zero-as-null-pointer-constant.