QUIC: fixed bulding perl module by reducing header pollution. The ngx_http_perl_module module doesn't have a notion of including additional search paths through --with-cc-opt, which results in compile error incomplete type 'enum ssl_encryption_level_t' when building nginx without QUIC support. The enum is visible from quic event headers and eventually pollutes ngx_core.h. The fix is to limit including headers to compile units that are real consumers.

--- a/src/event/ngx_event_quic.c
+++ b/src/event/ngx_event_quic.c
@@ -7,6 +7,8 @@
 #include <ngx_config.h>
 #include <ngx_core.h>
 #include <ngx_event.h>
+#include <ngx_event_quic_transport.h>
+#include <ngx_event_quic_protection.h>
 
 
 /*  0-RTT and 1-RTT data exist in the same packet number space,