Rollup merge of #77146 - Mark-Simulacrum:xpyinstall, r=alexcrichton
Rollup merge of #77146 - Mark-Simulacrum:xpyinstall, r=alexcrichton

Install std for non-host targets

It seems reasonable that when configuring various targets you'd expect all of them to get std installed, even if you're not building compiler toolchains for each of those.

cc #76990

r? @alexcrichton

aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust