Make depends: of windows.compile_resources() include-able

Add the output directories for any custom target in depends: to the resource
compiler include path

mesonbuild/interpreter.py

@@ -854,6 +854,10 @@ class CustomTargetHolder(TargetHolder):
     def __delitem__(self, index):
         raise InterpreterException('Cannot delete a member of a CustomTarget')
 
+    def outdir_include(self):
+        return IncludeDirsHolder(build.IncludeDirs('', [], False,
+                                                   [self.interpreter.backend.get_target_dir(self.held_object)]))
+
 class RunTargetHolder(InterpreterObject, ObjectHolder):
     def __init__(self, name, command, args, dependencies, subdir, subproject):
         InterpreterObject.__init__(self)

mesonbuild/modules/windows.py

@@ -20,6 +20,7 @@ from ..mesonlib import MesonException, extract_as_list
 from . import get_include_args
 from . import ModuleReturnValue
 from . import ExtensionModule
+from ..interpreter import CustomTargetHolder
 from ..interpreterbase import permittedKwargs, FeatureNewKwargs
 
 class WindowsModule(ExtensionModule):
@@ -38,6 +39,9 @@ class WindowsModule(ExtensionModule):
         extra_args = mesonlib.stringlistify(kwargs.get('args', []))
         wrc_depend_files = extract_as_list(kwargs, 'depend_files', pop = True)
         wrc_depends = extract_as_list(kwargs, 'depends', pop = True)
+        for d in wrc_depends:
+            if isinstance(d, CustomTargetHolder):
+                extra_args += get_include_args([d.outdir_include()])
         inc_dirs = extract_as_list(kwargs, 'include_directories', pop = True)
         for incd in inc_dirs:
             if not isinstance(incd.held_object, (str, build.IncludeDirs)):