devel/py-grpcio: fix build on powerpc(64)
Some mingling with headers is required to build abseil properly.
BoringSSL doesn't support powerpc and powerpc64 at all, only powerpc64le (ppc64le) is supported, so use system OpenSSL. BoringSSL is used because ALPN support is required, but it was implemented back in OpenSSL 1.0.2, which even stable/11 branch has. There's no need to use external SSL library at all.
Bump PORTREVISION because of package change.
PR: 248550
Approved by: vanilla (maintainer)
Approved by: portmgr (fix build blanket)
99e97b4601