Removed upstreamed patch:
100-build-on-OpenWrt.patch

Signed-off-by: DENG Qingfang <dengqf6@mail2.sysu.edu.cn>

Signed-off-by: Rosen Penev <rosenp@gmail.com>

Refreshed patch.

Added PKG_LICENSE_FILES.

Added --as-needed linker flag for slightly smaller size.

Removed -O2 hack to get it to compile. As part of this, removed a bunch of
CFLAGS that are normally passed which potentially affect compilation with
Os.

Signed-off-by: Rosen Penev <rosenp@gmail.com>