driver: Followup to d711563fe1bf8fa6810bc34ac92a2fd3150290ed: actually make the driver reentrant.

Re-fixes #305.

zsh-syntax-highlighting.zsh

@@ -286,17 +286,17 @@ _zsh_highlight_bind_widgets()
 
       # User defined widget: override and rebind old one with prefix "orig-".
       user:*) zle -N $prefix-$cur_widget ${widgets[$cur_widget]#*:}
-              eval "_zsh_highlight_widget_${(q)cur_widget}() { _zsh_highlight_call_widget ${(q)prefix}-${(q)cur_widget} -- \"\$@\" }"
-              zle -N $cur_widget _zsh_highlight_widget_$cur_widget;;
+              eval "_zsh_highlight_widget_${(q)prefix}-${(q)cur_widget}() { _zsh_highlight_call_widget ${(q)prefix}-${(q)cur_widget} -- \"\$@\" }"
+              zle -N $cur_widget _zsh_highlight_widget_$prefix-$cur_widget;;
 
       # Completion widget: override and rebind old one with prefix "orig-".
       completion:*) zle -C $prefix-$cur_widget ${${(s.:.)widgets[$cur_widget]}[2,3]} 
-                    eval "_zsh_highlight_widget_${(q)cur_widget}() { _zsh_highlight_call_widget ${(q)prefix}-${(q)cur_widget} -- \"\$@\" }"
-                    zle -N $cur_widget _zsh_highlight_widget_$cur_widget;;
+                    eval "_zsh_highlight_widget_${(q)prefix}-${(q)cur_widget}() { _zsh_highlight_call_widget ${(q)prefix}-${(q)cur_widget} -- \"\$@\" }"
+                    zle -N $cur_widget _zsh_highlight_widget_$prefix-$cur_widget;;
 
       # Builtin widget: override and make it call the builtin ".widget".
-      builtin) eval "_zsh_highlight_widget_${(q)cur_widget}() { _zsh_highlight_call_widget .${(q)cur_widget} -- \"\$@\" }"
-               zle -N $cur_widget _zsh_highlight_widget_$cur_widget;;
+      builtin) eval "_zsh_highlight_widget_${(q)prefix}-${(q)cur_widget}() { _zsh_highlight_call_widget .${(q)cur_widget} -- \"\$@\" }"
+               zle -N $cur_widget _zsh_highlight_widget_$prefix-$cur_widget;;
 
       # Incomplete or nonexistent widget: Bind to z-sy-h directly.
       *)