ld
-l namespec
搜尋 libnamespec.so => libnamespec.a
-l :filename
搜尋 filename
另外注意 -l ordering
link library需要的dependeny會往後找而不是往前找，如果有前後循環相依的問題可用–start-group archives –end-group來處理
-static or -Bdynamic: it affects library searching for -l options which follow it.