[Bug 138] add exec to yacc script

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@1040 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/bison-inst.xml

@@ -20,7 +20,7 @@ following:</para>
 #!/bin/sh
 # Begin /usr/bin/yacc
 
-/usr/bin/bison -y "$@"
+exec /usr/bin/bison -y "$@"
 
 # End /usr/bin/yacc
 <userinput>EOF</userinput>