`pkg-config`:
```
-$ pkg-config --variable=systemuidmax systemd
+$ pkg-config --variable=system_uid_max systemd
999
-$ pkg-config --variable=dynamicuidmin systemd
+$ pkg-config --variable=dynamic_uid_min systemd
61184
-$ pkg-config --variable=dynamicuidmax systemd
+$ pkg-config --variable=dynamic_uid_max systemd
65519
-$ pkg-config --variable=containeruidbasemin systemd
+$ pkg-config --variable=container_uid_base_min systemd
524288
-$ pkg-config --variable=containeruidbasemax systemd
+$ pkg-config --variable=container_uid_base_max systemd
1878982656
```