Properly find X libs are runtime

Index: src/meson.build
--- src/meson.build.orig
+++ src/meson.build
@@ -267,6 +267,7 @@ libcairo_dep = declare_dependency(link_with: libcairo,
 pkgmod.generate(libcairo,
   description: 'Multi-platform 2D graphics library',
   subdirs: [meson.project_name()],
+  libraries: ['-Wl,-rpath-link,${X11BASE}/lib'],
 )
 
 meson.override_dependency('cairo', libcairo_dep)