Add custom ct-ng config file of gcc 6.5.0 build with Pi 1 support

[artynet]

I'd like to submit this sample file for a new updated toolchain based on gcc v6.5.0. It is built over the latest trunk of crosstools-ng

[popcornmix]

I build a toolchain using latest ct-ng and it builds fine. What's the reason for choosing gcc 6.5.0?

buster uses gcc 8.3.0 which would seem like more natural choice for a version to bump to.

[artynet]

I just replicated the Debian Stretch base toolchain (binutils, gcc, kernel and glibc)....it seemed a more natural choice to me making a "small jump" from gcc v4 to gcc v6. I think you should provide an updated pre-built config reflecting the new ct-ng syntax...that's my take on this contribution.

For sure it will be a starting point for user wanting to build a toolchain from scratch and/or edit some additional options....