Both functions took a QString for the input file name, but while the ELF
parser had an optional QLibrary pointer (which was never null) where to
store the error string, the Mach-O parser received a pointer to a
QString. So make both of them take a single in/out QString pointer,
which has the file name on input and is cheap for us because of COW.
Drive-by fix the name of the static function in qmachparser.cpp from
"ns" (which stood for "not suitable") to "notfound".
Change-Id: I3eb1bd30e0124f89a052fffd16a8182f4f8541c3
Reviewed-by: Lars Knoll <lars.knoll@qt.io>