libcrypto: Fix integer comparison in evp_cipher_aead_encrypt()
src/libcrypto.c:773:27: warning: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Wsign-compare] <--[cc] if (rc != 1 || outlen != len - aadlen) { ^~ Signed-off-by: Andreas Schneider <asn@cryptomilk.org>