OpenRC; usage: A few changes.

1. No need to escape the space in `set -u` in the sed.
2. `chmod +x` the udevd service.
3. Add `-f` to the `ln` agetty command.

Thanks to Thomas Trepl for these fixes.

chapter08/openrc.xml

@@ -43,7 +43,7 @@
 
     <para>Fix a script to allow a normal installation:</para>
 
-<screen remap="pre"><userinput>sed -i '/set\ -u/d' tools/meson_final.sh</userinput></screen>
+<screen remap="pre"><userinput>sed -i '/set -u/d' tools/meson_final.sh</userinput></screen>
 
     <para>Prepare OpenRC for compilation:</para>
 

chapter09/usage.xml

@@ -91,7 +91,7 @@
   services:</para>
 
 <screen><userinput>for i in $(seq 1 6); do
-  ln -sv agetty /etc/init.d/agetty.tty$i
+  ln -sfv agetty /etc/init.d/agetty.tty$i
   rc-update add agetty.tty$i default
 done</userinput></screen>
 
@@ -148,6 +148,7 @@ start()
 }</literal>
 EOF
 
+chmod +x /etc/init.d/udevd
 rc-update add udevd boot</userinput></screen>
 
     <para>