Backport the patch from upstream:
https://github.com/gcc-mirror/gcc.git [commit beb921e]
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=269925
Add the premark_used_variables function, meanwhile do not mark
not premarked external variables in prune_unused_types_walk.
(From OE-Core rev: 7edf5725631e69c22627e41ecf5de3222f1d624b)
Signed-off-by: Zhixiong Chi <zhixiong.chi@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
