Lines should be identified by a TSourceLoc object,
which is currently typedefed to an int, but should
be changed to a struct soon, so making sure the
parser functions can handle the change.

Change-Id: Iaafad862dd1078591757695bf205279e7c4202cf
Reviewed-on: https://swiftshader-review.googlesource.com/3513Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>