[install] make -C languages reallyall

[rurban]

provide a target to do "make all" for all languages

"make build" is the default target (lang.dummy), but there's no target besides "make installable" to make all additional language targets.

eq. to $ cd languages $ for d in *; do test -e $d/Makefile && make -C $d all; done

[allison]

Skip. Languages won't be installed by the core Parrot makefile (aside from core tools like nqp).