Feature/linux 32 musl

[bcardiff]

Automate linux 32 bits binaries as in 64 bits. Even use the same Dockerfile to keep packages layout in sync.

• $ make all will build 64 and 32 bits packages
• $ make all64 will build 32 bits packages
• $ make all32 will build 32 bits packages

This procedure was already checked in circleci at https://circleci.com/gh/crystal-lang/crystal/6798#artifacts/containers/0

[RX14]

Looks really good, just 2 nitpicks and a small makefile rename.

[bcardiff]

Nitpicks addressed

[RX14]

@bcardiff what about the makefile rename?

I'd rename all the 64bits makefile targets to end in 64. Then have an all32, all64 and keep all as all targets (32 and 64 bit)

[bcardiff]

64 suffix added in all the places except in the environment variable used as parameter. The updated test is been tested at https://circleci.com/workflow-run/90e76c67-8ebb-4b3e-a616-0c638cf6c3e8