qt4.inc: expand the package name for multilib case
in the qt4.inc python annomyous code, there is case where package name
is set to "${QT_BASE_LIB}-tool", and FILE_${QT_BASE_LIB}-tool is set to xxx.
here QT_BASE_NAME=qt4. multilib.bbclass will try to rename the FILE_qt4_tool to
FILE_lib64_qt4_tool. unfortunately, there is only FILE_${QT_BASE}-tool, no
FILE_qt4-tool, so FILE_lib64_qt4_tool will not be defined.
to fix this issue, this patch expand the QT_BASE_LIB when assigning the package
name.
