external/mambo: Add support for readline if it exists

Add support for tclreadline package if it is present.
This patch loads the package and uses it when the
simulation stops for any reason.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

external/mambo/skiboot.tcl

@@ -1,6 +1,17 @@
 # need to get images path defined early
 source $env(LIB_DIR)/ppc/util.tcl
 
+#
+# Call tclreadline's Loop to move to friendlier
+# commandline if one exists
+#
+proc readline { } {
+    set readline [catch { package require tclreadline }]
+    if { $readline == 0 } {
+        ::tclreadline::Loop
+    }
+}
+
 proc mconfig { name env_name def } {
     global mconf
     global env
@@ -531,5 +542,7 @@ epapr::of2dtb mysim $mconf(epapr_dt_addr)
 mysim mode fastest
 
 if { [info exists env(SKIBOOT_AUTORUN)] } {
-    mysim go
+    if [catch { mysim go }] {
+	readline
+    }
 }