* crypto_stream_chacha20_ietf_xor_ic() was first available when libsodium was bumpped to version major 8. Debian jessie still uses major 7 minor 2, so check SODIUM_LIBRARY_VERSION_MAJOR and keep backwards compatibility.
* crypto_stream_chacha20_ietf_xor_ic() was first available when libsodium was bumped to version major 8. Debian jessie still uses major 7 minor 2, so check SODIUM_LIBRARY_VERSION_MAJOR and maintain backward compatibility.
