backend/ninja: Add order dependencies for generated sources in rust

mesonbuild/backend/ninjabackend.py

@@ -1582,6 +1582,9 @@ int dummy;
         # Compiler args for compiling this target
         args += compilers.get_base_compile_args(base_proxy, rustc)
         self.generate_generator_list_rules(target)
+
+        orderdeps = [os.path.join(t.subdir, t.get_filename()) for t in target.link_targets]
+
         main_rust_file = None
         for i in target.get_sources():
             if not rustc.can_compile(i):
@@ -1598,6 +1601,7 @@ int dummy;
                     fname = i
                 if main_rust_file is None:
                     main_rust_file = fname
+                orderdeps.append(fname)
         if main_rust_file is None:
             raise RuntimeError('A Rust target has no Rust sources. This is weird. Also a bug. Please report')
         target_name = os.path.join(target.subdir, target.get_filename())
@@ -1635,7 +1639,6 @@ int dummy;
         args += target.get_extra_args('rust')
         args += rustc.get_output_args(os.path.join(target.subdir, target.get_filename()))
         args += self.environment.coredata.get_external_args(target.for_machine, rustc.language)
-        orderdeps = [os.path.join(t.subdir, t.get_filename()) for t in target.link_targets]
         linkdirs = OrderedDict()
         for d in target.link_targets:
             linkdirs[d.subdir] = True
@@ -1682,7 +1685,7 @@ int dummy;
                 args += ['-C', 'link-arg=' + rpath_arg + ':' + os.path.join(rustc.get_sysroot(), 'lib')]
         compiler_name = self.get_compiler_rule_name('rust', target.for_machine)
         element = NinjaBuildElement(self.all_outputs, target_name, compiler_name, main_rust_file)
-        if len(orderdeps) > 0:
+        if orderdeps:
             element.add_orderdep(orderdeps)
         element.add_item('ARGS', args)
         element.add_item('targetdep', depfile)