Ensure existence of the target directory in repackage_system_suitesparse4.make

Fixes #6039
Don't emit convert_tuple calls when no conversion is necessary
Integrate gsl-shell/luajit into microbenchmarks

- Also update command to get Julia version info.
- Renames label for gsl-shell/lua tests from gsl_shell to lua.
- Remove non-working external BLAS usage warning

Closes #1662.
Merge pull request #6430 from JuliaLang/cjh/fix-1662

Integrate gsl-shell/luajit into microbenchmarks
Add support for multiline comments

I'm unclear about the purpose of the `b` flag, but it seems to work
fix #6415
Avoid some unnecessary buffer copying in REPL.jl
Fix #5770 (testall output)

thanks to @nolta
Prevent excessive refresh of REPL state

With the recent libuv async change and depending on the terminal emulator
there was really bad flickering on some systems everytime the input area was
refreshed. This fixes that by writing the entire refresh at once which most terminal emulators will draw in one go. There is still a small nit that we do two redraws when exiting from search, but that will have to be done another day.
Well, maybe a little more refreshing

Restore line refreshing after ^A ^E
Don't export symbols from Core that shouldn't be called directly
Merge pull request #6421 from JuliaLang/sjk/convert-tuple

Don't emit convert_tuple calls when no conversion is necessary
Merge pull request #6443 from JuliaLang/sjk/fewer-exports

Don't export symbols from Core that shouldn't be called directly
Merge pull request #6440 from rsrock/rsr/emacs-julia-mode

Add support for multiline comments
Merge commit '5446623f98563fd9038975fb11810d5a70e2d837' into jn/6415
Merge pull request #6158 from Manticore/patch-2

Ensure existence of the target directory in repackage_system_suitesparse4.make
More useful error message when spawn fails
Merge pull request #6449 from tkelman/patch-4

More useful error message when spawn fails