Simple question about mux

As we all know, when there is a multiple clocks in a design. we can use mux to control ,and the output of the mux should be connected to a global buffer. However, in the older families, such as APEK 20K , 20KE,and APEX II and so on,the output of the mux could not connect to a global buffer. So I want to know wether It is supported by all the new families, such as cyclone cyclone II, In addition, does Max Max II do?