c-ares: AutoTools does not set CARES_RANDOM_FILE during cross compilation

A flaw was found in c-ares. This issue occurs when cross-compiling c-ares and using the autotools build system, CARESRANDOMFILE will not be set, as seen when cross-compiling aarch64 android. As a result, it will downgrade to rand, which could allow an attacker to utilize the lack of entropy by no...