• Operating system + version: DragonflyBSD (following master)

Following the installation instructions on DragonFly, I ran into two problems:

• -buildmode=pie not supported on dragonfly/amd64
  • I fixed this by deleting that flag from Makefile
• "The operating system DragonFly is not supported". when I try to run gmake hosts-chromium-user PREFIX=$HOME/.local
  • I fixed this by replacing Linux|*BSD) Linux|*BSD|DragonFly) in the case statement in the Makefile.

Now it seems to work (I successfully got it to fill in a password in Chromium.)

I can try to put together a pull request if you like. I guess you don't want to remove -buildmode=pie everywhere, so I'd need to figure out how to enable it conditionally.