NodeOS cross toolchain

This package generate a cross-compiler based on gcc and
musl ready to use on the NodeOS build system, but could be used
by other systems. You can be able to configure the target of the cross-compiler
by setting some optional build flags or environment variables:

- -b/BITS: select between 32 or 64 - only affects x86 builds
- -c/CPU: by default it will generate for the current CPU
- -M/MACHINE: target machine according QEmu definitions

This bin folder contain placeholders for npm during the install step. They
are being replaced later during the install process to their correct symlinks.