When checking the active window before sending a focus event, we were previously sending the state-changed:focused first, causing Orca to read the focused control before the name of the newly-activated window.
Since we do not install WindowsBase.dll for Mono 2.5 and up, it is better for the .pc file not to assume that it is under $prefix; avoids potential build problems.
requested by Mozilla-a11y team.
Fixes BNC #489388 and building with Mono 2.8
invalid handles. Part of BNC #489388
BNC#635778: ComboBox is missing ExpandCollapsePattern
IsOffScreen. BNC #572216 and BNC #572301.