remove unused definition of jl_callback_t
fix syntax error in deps/Makefile
fix #7727, scheduling bug in `produce`
improve modules chapter of manual. various mistakes and omissions fixed.
Only catch icc in preprocessor defines
update perf tests for removed deprecations
improve compile-time method matching logic

don't consider typevars unmatched if we can prove that they would be
matched by any actual call.

fixes #5575

slightly expand some array constructor signatures so `Type{<:Top}` matches
them, not just `Type{<:Any}`.