qobject_to_qbool() crashes on null, which is a trap for the unwary.
Return null instead, and simplify a few callers.
Backports commit 14b6160099f0caf5dc9d62e637b007bc5d719a96 from qemu
These macros expand into error class enumeration constant, comma,
string. Unclean. Has been that way since commit 13f59ae.
The error class is always ERROR_CLASS_GENERIC_ERROR since the previous
commit.
* Prepend every use of a QERR_ macro by ERROR_CLASS_GENERIC_ERROR, and
delete it from the QERR_ macro. No change after preprocessing.
* Rewrite error_set(ERROR_CLASS_GENERIC_ERROR, ...) into
error_setg(...). Again, no change after preprocessing.
Backports commit c6bd8c706a799eb0fece99f468aaa22b818036f3 from qemu
We require a C99 compiler, so let's use 'bool' instead of 'int'
when dealing with boolean values. There are few enough clients
to fix them all in one pass.
Backports commit fc48ffc39ed1060856475e4320d5896f26c945e8 from qemu
