doc: How to build for SELinux by cargo (#8964)

README.md

@@ -1,6 +1,6 @@
 <!-- markdownlint-disable MD033 MD041 MD002 -->
 <!-- markdownlint-disable commands-show-output no-duplicate-heading -->
-<!-- spell-checker:ignore markdownlint ; (options) DESTDIR UTILNAME manpages reimplementation oranda -->
+<!-- spell-checker:ignore markdownlint ; (options) DESTDIR UTILNAME manpages reimplementation oranda libclang -->
 <div class="oranda-hide">
 <div align="center">
 
@@ -120,6 +120,12 @@ cargo build --release --features windows
 cargo build --release --features unix
 ```
 
+To build SELinux-specific features, including `chcon` and `runcon`, ensure that `libselinux` 
+and `libclang` are installed on your system. Then, run the following command:
+```
+cargo build --release --features unix,feat_selinux
+```
+
 If you don't want to build every utility available on your platform into the
 final binary, you can also specify which ones you want to build manually. For
 example: