support compile on windows when disable __STATIC_QT if static qt lib not installed

Without installation of static qt plugin lib, Qt5SvgIcon_LIBRARIES_RELEASE not found and

may cause following error

Error	1	error LNK1107: invalid or corrupt file: cannot read at 0x2D8	C:\Qt\Qt5.2.0\5.2.0\msvc2012\plugins\platforms\qminimal.dll	1

, so improve to support change KH_STATIC_QT to 0 to disable this.