[gcalctool] Add EN DASH as subtract token

[Robert Ancell <rancell src gnome org>]

commit acf9296a3c5024cacfe4d90a5fda2b86e45d0ccd
Author: PioneerAxon <arth svnit gmail com>
Date:   Sun Aug 19 14:33:38 2012 +0530

    Add EN DASH as subtract token
    
    EN DASH ("â") is used by Open Office. Which caused "Malformed Expression".

 src/prelexer.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/prelexer.c b/src/prelexer.c
index a22dd0d..723b190 100644
--- a/src/prelexer.c
+++ b/src/prelexer.c
@@ -139,7 +139,7 @@ pl_get_next_token(PreLexerState* state)
     if(pl_compare_all(ch, 1, (gchar*[]){"+"}))
         return T_ADD;
 
-    if(pl_compare_all(ch, 2, (gchar*[]){"-","â"}))
+    if(pl_compare_all(ch, 3, (gchar*[]){"-","â","â"}))
         return T_SUBTRACT;
 
     if(pl_compare_all(ch, 2, (gchar*[]){"*","Ã"}))