fiptool is a host tool, used in a firmware generation pipeline, but it's
not treated as such, leading to the build breakage on the hosts which
don't have {Open,Libre}SSL dev package installed:
In file included from fiptool.h:16:0,
from fiptool.c:19:
fiptool_platform.h:18:27: fatal error: openssl/sha.h:
No such file or directory
# include <openssl/sha.h>
So this patch promotes fiptool into the host tool with proper host
include and library paths under STAGING_DIR.
Ref: https://github.com/openwrt/openwrt/pull/2267
Signed-off-by: Petr Štetiar <ynezz@true.cz>
