Add 'const' to string casts?

gcc dislikes this cast (in xslt.h):

    /**
     * XSLT_NAMESPACE:
     *
     * The XSLT specification namespace.
     */
    #define XSLT_NAMESPACE ((xmlChar *) "http://www.w3.org/1999/XSL/Transform")

The error is:

    warning: cast discards qualifiers from pointer target type

Can this be changed to:

    #define XSLT_NAMESPACE ((const xmlChar *) "http://www.w3.org/1999/XSL/Transform")

to avoid the warning?

Thanks,
 Phil