diff --git a/src/xrt/include/xrt/xrt_openxr_includes.h b/src/xrt/include/xrt/xrt_openxr_includes.h
index 6818ce8d2..f956fb3f9 100644
--- a/src/xrt/include/xrt/xrt_openxr_includes.h
+++ b/src/xrt/include/xrt/xrt_openxr_includes.h
@@ -9,12 +9,8 @@
 
 #pragma once
 
-// Move these to the build system instead.
-#define XR_USE_GRAPHICS_API_OPENGL
-#define XR_USE_GRAPHICS_API_OPENGL_ES
+//! @todo Move these to the build system instead.
 #define XR_USE_GRAPHICS_API_VULKAN
-#define XR_USE_PLATFORM_XLIB
-#define XR_USE_PLATFORM_EGL
 #define XR_USE_TIMESPEC 1
 
 #ifdef XR_USE_PLATFORM_XLIB
diff --git a/src/xrt/state_trackers/oxr/CMakeLists.txt b/src/xrt/state_trackers/oxr/CMakeLists.txt
index 4b85e447f..f7ad44390 100644
--- a/src/xrt/state_trackers/oxr/CMakeLists.txt
+++ b/src/xrt/state_trackers/oxr/CMakeLists.txt
@@ -43,6 +43,18 @@ set(OXR_SOURCE_FILES
 	oxr_xdev.c
 	)
 
+if(BUILD_WITH_OPENGL)
+	add_definitions(-DXR_USE_GRAPHICS_API_OPENGL -DXR_USE_GRAPHICS_API_OPENGL_ES)
+endif()
+
+if(BUILD_WITH_XLIB)
+	add_definitions(-DXR_USE_PLATFORM_XLIB)
+endif()
+
+if(BUILD_WITH_EGL)
+	add_definitions(-DXR_USE_PLATFORM_EGL)
+endif()
+
 # Use OBJECT to not create a archive, since it just gets in the way.
 add_library(st_oxr OBJECT ${OXR_SOURCE_FILES})
 
diff --git a/src/xrt/state_trackers/oxr/meson.build b/src/xrt/state_trackers/oxr/meson.build
index 53189bd43..cfaeadd65 100644
--- a/src/xrt/state_trackers/oxr/meson.build
+++ b/src/xrt/state_trackers/oxr/meson.build
@@ -1,6 +1,19 @@
 # Copyright 2019, Collabora, Ltd.
 # SPDX-License-Identifier: BSL-1.0
 
+compile_args = []
+if x11.found()
+	compile_args += ['-DXR_USE_GRAPHICS_API_OPENGL', '-DXR_USE_GRAPHICS_API_OPENGL_ES']
+endif
+
+if egl.found()
+	compile_args += ['-DXR_USE_PLATFORM_EGL']
+endif
+
+if opengl.found()
+	compile_args += ['-DXR_USE_PLATFORM_XLIB']
+endif
+
 lib_st_oxr = static_library(
 	'st_oxr',
 	files(
@@ -43,4 +56,6 @@ lib_st_oxr = static_library(
 		external_include,
 	],
 	dependencies: [aux, vulkan],
+	c_args: compile_args,
+	cpp_args: compile_args,
 )