In SR0610, the TCB is made private, so the task environ field used by
the environ macro is no longer visible.  Arguably this is a bug, however
a more correct approach is to use accessor functions to retrieve this
field and not use the environ macro, thus avoiding the problem.

2019-07-10  Doug Rupp  <rupp@adacore.com>

gcc/ada/

	* env.c (__gnat_environ): Reformulate to also work for
	vxworks7r2 SR0610.

From-SVN: r273332