Fix -Wextra warning in generated .pb.c files.

Compile the generated files with the same extra-strict
settings as the core, in order to detect problems in tests.

Update issue 32
Status: FixedInGit

tests/Makefile

@@ -11,6 +11,9 @@ all: breakpoints $(TESTS) run_unittests
 clean:
 	rm -f $(TESTS) person.pb* alltypes.pb* *.o *.gcda *.gcno
 
+%.pb.o: %.pb.c %.pb.h
+	$(CC) $(CFLAGS) $(CFLAGS_CORE) -c -o $@ $<
+
 %.o: %.c
 %.o: %.c $(DEPS)
 	$(CC) $(CFLAGS) -c -o $@ $<