I would like to revive this issue, as the only person seemingly distributing a 32-bit Swift toolchain now, with my 5.6.1 build for Android armv7. I had to apply a commit from trunk to get the compiler to build and it appears to work well now, other than a runtime regression and a few prior bugs.
Given the upcoming embedded push and focus on performance, we should set up a CI for some 32-bit platform, to make sure it keeps building. I had to apply three patches to include/swift/ to get the Apr. 17 snapshot of the 5.7 branch to build for Android armv7 but the resulting compiler segfaults, haven't looked into why. I also recently reported some trunk regressions when building the stdlib for armv7 on my Android CI.
@futurejones, I don't know how well AArch32 support works on linux AArch64, would you be willing to set up 32-bit builds as part of your upcoming ARM CI? @ColemanCDA, you may be interested in getting a proper 32-bit CI going too, considering your recent 32-bit pulls.