PR c/57773
	* doc/implement-c.texi: Mention that other integer types are
	permitted as bit-field types in strictly conforming mode.
c/
	* c-decl.c (check_bitfield_type_and_width): Warn for implementation
	defined bit-field types only in ISO C.
testsuite/
	* gcc.dg/pr57773.c: New test.

From-SVN: r206373