rust: add auto-generated header to sys.rs

We don't keep bindgen's autogenerated do not edit line as it contains
the bindgen version which could break the CI check for out of date
bindings. So add our own do not edit line.

Ticket: #7341

rust/Makefile.am

@@ -117,6 +117,7 @@ if HAVE_BINDGEN
 		$(abs_top_srcdir)/src/bindgen.h \
 		-- \
 		-DHAVE_CONFIG_H -I../src -I../rust/gen $(CPPFLAGS)
+	sed -i '1i\// This file is automatically generated. Do not edit.\n' sys/src/sys.rs
 else
 	@echo "error: bindgen not installed, can't update bindings"
 	exit 1

rust/sys/src/sys.rs

@@ -1,3 +1,5 @@
+// This file is automatically generated. Do not edit.
+
 #[repr(u32)]
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub enum AppProtoEnum {