diff --git a/meson.build b/meson.build
index 0727fd5589..f7a3f3ada2 100644
--- a/meson.build
+++ b/meson.build
@@ -1594,6 +1594,7 @@ generate_gperfs = find_program('tools/generate-gperfs.py')
 
 subdir('po')
 subdir('catalog')
+subdir('src/libudev')
 subdir('src/systemd')
 subdir('src/basic')
 subdir('src/libsystemd')
@@ -1673,7 +1674,6 @@ update_dbus_docs_py = find_program('tools/update-dbus-docs.py')
 # usually, but not always, installed in /bin.
 public_programs = []
 
-subdir('src/libudev')
 subdir('src/shared')
 subdir('src/core')
 subdir('src/shutdown')
diff --git a/src/systemd/meson.build b/src/systemd/meson.build
index 96cbf46620..c9c484b411 100644
--- a/src/systemd/meson.build
+++ b/src/systemd/meson.build
@@ -64,9 +64,12 @@ if add_languages('cpp', required : false)
         if cxx.has_argument('-std=c++17')
                 opts += [['c++', '-std=c++17']]
         endif
+        if cxx.has_argument('-std=c++20')
+                opts += [['c++', '-std=c++20']]
+        endif
 endif
 
-foreach header : _systemd_headers + _not_installed_headers + ['../libudev/libudev.h']
+foreach header : _systemd_headers + _not_installed_headers + [libudev_h_path]
         foreach opt : opts
                 std_name = opt.length() == 2 ? '_'.join(opt[1].split(':')) : ''
                 name = ''.join(['cc-', header.split('/')[-1], '_', opt[0], std_name])