amext-msvc: random cleanups
amext-msvc: random cleanups

rabbitt/libusual,mgjv/libusual,rabbitt/libusual,markokr/libusual,mgjv/libusual,ifduyue/libusual,ifduyue/libusual,markokr/libusual,rabbitt/libusual,mgjv/libusual,rabbitt/libusual,ifduyue/libusual,mgjv/libusual,ifduyue/libusual,markokr/libusual,markokr/libusual