QUIC: added support for the Tongsuo SSL library.

For the needs of QUIC, this is basically openssl-1.1.1h with
BoringSSL-compatible QUIC support.

The library was developed by AliBaba and was previously called BabaSSL,
thus macro names [1].

[1] https://github.com/Tongsuo-Project/Tongsuo

src/event/quic/ngx_event_quic_ssl.c

@@ -12,6 +12,7 @@
 
 #if defined OPENSSL_IS_BORINGSSL                                              \
     || defined LIBRESSL_VERSION_NUMBER                                        \
+    || defined BABASSL_VERSION_NUMBER                                         \
     || NGX_QUIC_OPENSSL_COMPAT
 #define NGX_QUIC_BORINGSSL_API   1
 #endif