Add linux-armv7l-musl

[alexojegu]

This PR add a docker images:

• linux-armv7-musl: armv7 image with musl as libc

[alexojegu]

It is based on dockcross/linux-armv7l-musl. I have named the image as linux-armv7-musl, if it seems more appropriate I can change the name to linux-armv7l-musl.

The same in the Dockerfile, I have used:

ENV PREBUILD_ARCH arm
ENV PREBUILD_ARMV 7

But if it is more appropriate I can use (I'm not sure if this would work):

ENV PREBUILD_ARCH arm
ENV PREBUILD_ARMV 7l

[vweevers]

I assume dockcross had a reason for using arm7l in this image name (unlike others like dockcross/linux-armv7 - we just copied those names). Any guesses as to why? I don't know what the L represents or why it's significant for one image and not others.

[alexojegu]

I changed the name of everything from linux-armv7-musl to linux-armv7l-musl but kept the PREBUILD_ARMV as 7, if you want I can also change it to 7l.

I don't know what the L means either. This seems suggest: armv7l is little-endian v7.

[alexojegu]

Excuse me @vweevers, I don't know if I understood you correctly before. Are you waiting for me to modify PREBUILD_ARMV or just for you to get time?

[vweevers]

just for you to get time?

just that :)

[vweevers]

2.2.0