How do I import config header files?

[smac89]

Given the following config.in.h file:

#pragma once
#define MULTILINE(...) #__VA_ARGS__

#define UI_XML MULTILINE("${UI_XML}")

I added it to my xmake.lua using

target("ui.simple")
    set_kind("binary")
    set_default(true)
    ...
    set_configdir("$(buildir)/$(plat)/$(arch)/$(mode)")
    add_configfiles("c/config.in.h", {filename = "config.h"})
    add_files("c/ui.simple.c")
    on_load(function (target)
        local xml = io.readfile("c/ui.simple.xml")
        target:set("configvar", "UI_XML", xml)
    end)

It generates the following file (config.h):

#pragma once
#define MULTILINE(...) #__VA_ARGS__

#define UI_XML MULTILINE("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\
<!-- Generated with glade 3.40.0 -->\
<interface>\
  <requires lib=\"gtk+\" version=\"3.24\"/>\
  <!-- interface-css-provider-path marblemeterui.css -->\
  <object class=\"GtkWindow\">\
    <property name=\"name\">mainwindow</property>\
    <property name=\"can-focus\">False</property>\
    <property name=\"hexpand\">True</property>\
    <property name=\"vexpand\">True</property>\
    <property name=\"modal\">True</property>\
    <property name=\"window-position\">center</property>\
  ...
</interface>\
")

The code which uses the config is very simple (ui.simple.c):

#include "config.h"
#include <stdio.h>

int main()
{
  puts(UI_XML);
  return 0;
}

However, it won't compile. It complains about config.h not being found. How do I ensure it is found?

[smac89]

Looks like I was missing one important aspect which wasn't clear from the docs: Include the config directory

target("ui.simple")
  ...
  add_includedirs("$(buildir)/$(plat)/$(arch)/$(mode)")