diff --git a/meson.build b/meson.build
index 900176e41..5feb8338e 100644
--- a/meson.build
+++ b/meson.build
@@ -592,13 +592,13 @@ if build_xorg
     awk = find_program('awk')
 
     sdkconfig.set('prefix', get_option('prefix'))
-    sdkconfig.set('exec_prefix', get_option('prefix'))
-    sdkconfig.set('libdir', get_option('libdir'))
-    sdkconfig.set('includedir', get_option('includedir'))
-    sdkconfig.set('datarootdir', get_option('datadir'))
-    sdkconfig.set('moduledir', get_option('module_dir'))
-    sdkconfig.set('sdkdir', join_paths(get_option('includedir'), 'include'))
-    sdkconfig.set('sysconfigdir', join_paths(get_option('datadir'), 'X11/xorg.conf.d'))
+    sdkconfig.set('exec_prefix', '${prefix}')
+    sdkconfig.set('libdir', join_paths('${exec_prefix}', get_option('libdir')))
+    sdkconfig.set('includedir', join_paths('${prefix}', get_option('includedir')))
+    sdkconfig.set('datarootdir', join_paths('${prefix}', get_option('datadir')))
+    sdkconfig.set('moduledir', join_paths('${exec_prefix}', get_option('module_dir')))
+    sdkconfig.set('sdkdir', join_paths('${prefix}', get_option('includedir'), 'xorg'))
+    sdkconfig.set('sysconfigdir', join_paths('${datarootdir}', 'X11/xorg.conf.d'))
 
     sdkconfig.set('abi_ansic',
         run_command(awk, '-F', '[(,)]',
diff --git a/meson_options.txt b/meson_options.txt
index ce1ae80bd..5c7be0e26 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -19,7 +19,7 @@ option('builder_addr', type: 'string', description: 'Builder address', value: 'x
 option('builder_string', type: 'string', description: 'Additional builder string')
 
 option('log_dir', type: 'string')
-option('module_dir', type: 'string',
+option('module_dir', type: 'string', value: 'xorg/modules',
        description: 'X.Org modules directory')
 option('default_font_path', type: 'string')