tools: Fix protobuf compiler build with recent compilers

This is a manual backport of
https://github.com/protocolbuffers/protobuf/commit/01a05a53f40ca2ac5f0af10c6cc0810bee39b792

extras/tools/protobuf-fix-build.patch

+--- protobuf/src/google/protobuf/compiler/java/java_file.cc.old	2021-12-13 14:57:55.210153925 +0100
++++ protobuf/src/google/protobuf/compiler/java/java_file.cc	2021-12-13 14:58:03.734181392 +0100
+@@ -65,7 +65,7 @@
+ namespace {
+ 
+ struct FieldDescriptorCompare {
+-  bool operator ()(const FieldDescriptor* f1, const FieldDescriptor* f2) {
++  bool operator ()(const FieldDescriptor* f1, const FieldDescriptor* f2) const {
+     if(f1 == NULL) {
+       return false;
+     }

extras/tools/tools.mak

@@ -315,6 +315,7 @@ protobuf-$(PROTOBUF_VERSION).tar.gz:
 
 protobuf: protobuf-$(PROTOBUF_VERSION).tar.gz
 	$(UNPACK)
+	$(APPLY) $(TOOLS)/protobuf-fix-build.patch
 	$(MOVE)
 
 .buildprotoc: protobuf