www/vigil: fix build on powerpc
= note: ld: error: undefined symbol: __atomic_fetch_add_8
>>> referenced by threads_pthread.c
>>> libcrypto-lib-threads_pthread.o:(ossl_rcu_read_lock) in archive /wrkdirs/usr/ports/www/vigil/work/rustc6Mqxu5/libopenssl_sys-c63ab88b0f69bc0f.rlib