Problems with evolving feature test macros?

[Paul Eggert]

On 03/11/2014 12:13 PM, Rich Felker wrote:
>> It's typically only a minor annoyance.
> No, it's very unfortunate because defining _GNU_SOURCE breaks
> strerror_r, basename,
Even those glitches, which are indeed unfortunate, are minor 
annoyances.  You can easily fix the former with Autoconf's 
AC_FUNC_STERROR_R macro, for example, and that's what GNU applications 
commonly do.And basename is so broken that portable applications should 
avoid it and write their own.

The real problems in portability are elsewhere.  These problems are minor.