Fix PR63758 by using the _NSGetEnviron() API on Darwin

include/

	Roland McGrath  <roland@gnu.org>

	PR other/63758
	* environ.h: New file.

libiberty/

	Roland McGrath  <roland@gnu.org>
	Iain Sandoe  <iain@codesourcery.com>

	PR other/63758
	* pex-unix.c: Obtain the environment interface from settings in environ.h
	rather than in-line code.  Update copyright date.
	* setenv.c: Likewise.
	* xmalloc.c: Likewise.




git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@228942 138bc75d-0d04-0410-961f-82ee72b054a4