Re: libintl.h warnings with -Wundef

[Bruno Haible]

Christian Weisgerber wrote:
> Projects that include libintl.h and build with gcc -Wundef show warnings
> such as these:
> 
> /usr/local/include/libintl.h:91:25: warning: "__APPLE_CC__" is not defined
> /usr/local/include/libintl.h:113:24: warning: "__APPLE_CC__" is not defined

This -Wundef option is pointless:
  - Is its purpose to catch portability problems w.r.t. other compilers? No.
    All C compilers at least since 1980 have evaluated undefined identifiers
    in preprocessor expressions to 0.
  - Is its purpose to detect typos? No, because you recommend to avoid the
    warning by using the idiom   (defined X && X).  But when I have a typo
    in X and use this idiom nevertheless, copy&pasting the identifier as usual,
    my code will still be wrong and no warning will be flagged.

So I don't see a reason to do particular efforts for the sake of this warning.

Btw, you can get rid of the warning also by using the gcc command line
option "-isystem /usr/local/include" instead of "-I /usr/local/include".

Bruno