The logic added to install Perforce in Docker didn't work correctly, for

a couple of reasons.
First, we were basing our logic off of the build machine's architecture,

not the target architecture. When cross-building for X86 on ARM, we

wouldn't even try to install Perforce support at all. We needed to base

things off of $TARGETARCH instead of $BUILDARCH.
That didn't even matter though, as we never declared we needed that

variable. So we skipped the Perforce support in all cases.
And finally, even if that did work, we had the wrong command for

installing the p4 support. And we had some bash-isms that didn't work in

the shell used to execute these commands.
We now declare and use $TARGETARCH for the comparisons, and properly

install the p4 binary and p4python support whenever we're building

for X86.
Note that we can't build for ARM, as p4python still hasn't been

released for ARM.

Built for both ARM and X86, and checked the resulting P4 support in

both. Verified that we had it installed properly in X86, and didn't

have any of it in ARM.