Created attachment 197569 [details] [review]
add support for callback in field class to g-ir-compiler

Attempting to generate a gir and typelib from evolution-data-server camel I get a:
warning: element callback from state 14 is unknown, ignoring
** ERROR **: Caught NULL node, parent=is_key
error from g-ir-compiler.

It turns out g-ir-scanner made up a gir xml like:
<class>
  <field name="is_key">
    <callback name="is_key">
from CamelPartitionTable is_key  callback field:
http://git.gnome.org/browse/evolution-data-server/tree/camel/camel-partition-table.h#n115
struct _CamelPartitionTable {
	CamelObject parent;
	CamelPartitionTablePrivate *priv;

	CamelBlockFile *blocks;
	camel_block_t rootid;

	gint (*is_key)(CamelPartitionTable *cpi, const gchar *key, camel_key_t keyid, gpointer data);
	gpointer is_key_data;

	/* we keep a list of partition blocks active at all times */
	CamelDList partition;
};


I was unable from available reference of the gir XML format to decipher whether callback in a class field is correct and g-ir-compiler is lacking. In doubt I made up this patch to add support to g-ir-compiler to add this support.