为什么工具链名称有单独的OS和EABI字段。

For eg. arm-unknown-linux-gnueabi Now, once the OS i.e Linux is fixed, the C Library will be fixed (GLibc) and hence the calling convention and ABI being followed will be fixed. What is the requirement of 4th field i.e. ABI separately? Can a toolchain use a different ABI from the one used by underlying OS and LIBC. In that case how will libraries compiled by the said toolchain run on the OS?For eg. arm-unknown-linux-gnueabi Now, once the