Make --help actually work even if --prefix is not given

list --help in the README.md

Funded-by: IDEAS
Project: xSDK
Time: .1 hour
Reported-by: Alicia Marie Klinvex <[email protected]>

Author: BarrySmith

README.md

@@ -43,6 +43,8 @@ as well as some commonly needed external packages
 ##Useful Options
 
 ```no-highlight
+    --help  List all the possible options (most you will never need)
+    
     --download-mpich  Useful if you do not have an MPI installed on your machine.
 
     --with-blaslapack-dir="directory to locate BLAS and LAPACK"   Usually you should not need this.

installxSDK.sh

@@ -10,6 +10,7 @@ for i in "$@"
       echo "xSDK Installer help:"
       echo "--prefix=\"installation directory\" [--download-ideas] [other standard configure options such as mpicc=  etc]"
       SKIPMAKE="1"
+      PREFIX="dummy"      
     ;;
     --prefix=*)
       PREFIX="${i#*=}"