如何判断当前操作系统是否使用类似Linux或类似MacOSX的共享库？

I am aware that there are (at least) two radically different kinds of shared-library files on Unix-type systems. One is the kind used on GNU/Linux systems and probably other systems as well (with the filename ending in ".so") and the other used in Mac OS X, and also I am aware that there are (at least) two radica