diff --git a/meson.build b/meson.build
index 28799d8..047e523 100644
--- a/meson.build
+++ b/meson.build
@@ -72,11 +72,15 @@
 pc_conf = configuration_data()
 pc_conf.set('prefix', get_option('prefix'))
 pc_conf.set('exec_prefix', '${prefix}')
-pc_conf.set('libdir', '${exec_prefix}/' + get_option('libdir'))
-pc_conf.set('includedir', '${prefix}/' + get_option('includedir'))
-pc_conf.set('STARTUP_NOTIFICATION_PACKAGE', STARTUP_NOTIFICATION_PACKAGE)
+pc_conf.set('libdir', '${exec_prefix}' / get_option('libdir'))
+pc_conf.set('includedir', '${prefix}' / get_option('includedir'))
+if conf.has('HAVE_' + STARTUP_NOTIFICATION_PACKAGE.to_upper().underscorify())
+  pc_conf.set('STARTUP_NOTIFICATION_PACKAGE', STARTUP_NOTIFICATION_PACKAGE)
+endif
 pc_conf.set('X11_PACKAGE', X11_PACKAGE)
-pc_conf.set('XRES_PACKAGE', XRES_PACKAGE)
+if conf.has('HAVE_' + XRES_PACKAGE.to_upper().underscorify())
+  pc_conf.set('XRES_PACKAGE', XRES_PACKAGE)
+endif
 pc_conf.set('VERSION', meson.project_version())
 
 foreach pc: [PACKAGE_NAME, PACKAGE_NAME + '-uninstalled']