Introduce QError

QError is a high-level data type which represents an exception
in QEMU, it stores the following error information:

- class          Error class name (eg. "ServiceUnavailable")
- description    A detailed error description, which can contain
                 references to run-time error data
- filename       The file name of where the error occurred
- line number    The exact line number of the error
- function       The function name of where the error occurred
- run-time data  Any run-time error data

Signed-off-by: Luiz Capitulino <[email protected]>
Signed-off-by: Anthony Liguori <[email protected]>
diff --git a/qobject.h b/qobject.h
index 2270ec1..07de211 100644
--- a/qobject.h
+++ b/qobject.h
@@ -43,6 +43,7 @@
     QTYPE_QLIST,
     QTYPE_QFLOAT,
     QTYPE_QBOOL,
+    QTYPE_QERROR,
 } qtype_code;
 
 struct QObject;