[tracker] libtracker-sparql: Avoid compiler warning and cast const to non-const

[Martyn James Russell <mr src gnome org>]

commit db791b589fb73057d6c5fade30d929a8494cca3c
Author: Martyn Russell <martyn lanedo com>
Date:   Sat Oct 19 15:09:28 2013 +0100

    libtracker-sparql: Avoid compiler warning and cast const to non-const
    
    Used for traversing a char* converted to from a Vala String. We don't change
    the char, just the *.

 src/libtracker-sparql/tracker-utils.vala |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/src/libtracker-sparql/tracker-utils.vala b/src/libtracker-sparql/tracker-utils.vala
index 9b62dce..7e144a9 100644
--- a/src/libtracker-sparql/tracker-utils.vala
+++ b/src/libtracker-sparql/tracker-utils.vala
@@ -47,7 +47,12 @@ namespace Tracker.Sparql {
         */
        public string escape_string (string literal) {
                StringBuilder str = new StringBuilder ();
-               char *p = literal;
+
+               /* Shouldn't cast from const to non-const here, but we know
+                * the compiler is going to complain and it's just because
+                * Vala string manipulation doesn't allow us to do this more
+                * easily. */
+               char *p = (char*) literal;
 
                while (*p != '\0') {
                        size_t len = Posix.strcspn ((string) p, "\t\n\r\b\f\"\\");