SSL: fixed build with LibreSSL 2.8.0 (ticket #1605).
LibreSSL 2.8.0 "added const annotations to many existing APIs from OpenSSL,
making interoperability easier for downstream applications". This includes
the const change in the SSL_CTX_sess_set_get_cb() callback function (see
9dd43f4ef67e), which breaks compilation.
To fix this, added a condition on how we redefine OPENSSL_VERSION_NUMBER
when working with LibreSSL (see 382fc7069e3a). With LibreSSL 2.8.0,
we now set OPENSSL_VERSION_NUMBER to 0x1010000fL (OpenSSL 1.1.0), so the
appropriate conditions in the code will use "const" as it happens with
OpenSSL 1.1.0 and later versions.
diff --git a/src/event/ngx_event_openssl.h b/src/event/ngx_event_openssl.h
index 1962aa0..159deb7 100644
--- a/src/event/ngx_event_openssl.h
+++ b/src/event/ngx_event_openssl.h
@@ -36,8 +36,12 @@
#if (defined LIBRESSL_VERSION_NUMBER && OPENSSL_VERSION_NUMBER == 0x20000000L)
#undef OPENSSL_VERSION_NUMBER
+#if (LIBRESSL_VERSION_NUMBER >= 0x2080000fL)
+#define OPENSSL_VERSION_NUMBER 0x1010000fL
+#else
#define OPENSSL_VERSION_NUMBER 0x1000107fL
#endif
+#endif
#if (OPENSSL_VERSION_NUMBER >= 0x10100001L)
