Remove "-l concurrent.el" (now `make compile test` fails)
Fix: Invalid function: cc:dataflow-channel

Prior to this patch, `make clean compile test` fails even before
running tests with error message:

    Invalid function: cc:dataflow-channel

This is because the macro `cc:dataflow-test` is used in
`cc:dataflow-environment` which is prior to definition of
`cc:dataflow-test`.  To solve this, `(defmacro cc:dataflow-channel ...)`
is moved prior to `cc:dataflow-environment`.  For consistency, other
internal utility macros are moved alongside with it too.
Merge branch 'move-around-macros-in-concurrent' of https://github.com/tkf/emacs-deferred into tkf-move-around-macros-in-concurrent
fixed: the failure of semaphore2 test
Merge branch 'tkf-move-around-macros-in-concurrent'