[Bug libstdc++/69383] [6 Regression] r232586 breaks Firefox build

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69383

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Firefox could use
#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
#include_next <stdlib.h>
#undef _GLIBCXX_INCLUDE_NEXT_C_HEADERS
instead of just
#include_next <stdlib.h>
to get the old behavior I guess.