Re: [PATCH] warnings: Add gl_WARN_COMPLEMENT and gl_WARN_SUPPORTED.

[Bruno Haible]

Hi Simon,

What is the use of these macros gl_WARN_COMPLEMENT, gl_WARN_SUPPORTED?
They are not documented, and you haven't said what they are good for.

In particular, I don't see what anyone can do with the list of all
GCC supported warning options. While -Wall is widely applicable, most
other warnings is specific to a particular kind of coding style or kind of
application area. For example,
  - -Wunused is useful when the program has no function types, but produces
    useless warnings when callbacks and function types are used,
  - -Wfloat-equal is useful when you write numerical approximation algorithms,
    but produces useless warnings for implementations of basic functions like
    ceill or roundl,
  - -Waggregate-return is useful for programs that want portability to
    pre-ANSI-C compilers (!), but produces useless warnings for code that is
    nowadays considered normal,
  - -Wlong-long is useful for programs that want portability to 1995 compilers,
    but produces warnings for programs which require 64-bit integers (which
    gnulib does).

Bruno