dev: copy built binaries rather than symlinking them

[rickystewart]

This uses more disk space but is resilient to the confusing case
where your Bazel output_base gets deleted (either due to
bazel clean --expunge or if your output_base gets wiped due to a
macOS upgrade).

Release note: None

[cockroach-teamcity]

This change is 

[mari-crl]

Code LGTM!

To save disk space (and, though minor, IO time) for people who have their output_base on the same filesystem as their workspace, can we first attempt to hard link before falling back to copying if hard linking fails?

[rickystewart]

To save disk space (and, though minor, IO time) for people who have their output_base on the same filesystem as their workspace, can we first attempt to hard link before falling back to copying if hard linking fails?

I tried this but the restrictive permissions (no w) that Bazel has on the built binaries confuse things. For example after I dev build short if I try to rm cockroach then I get the following message:

cockroach$ rm cockroach
override r-xr-xr-x  ricky/wheel for cockroach? y

[mari-crl]

To save disk space (and, though minor, IO time) for people who have their output_base on the same filesystem as their workspace, can we first attempt to hard link before falling back to copying if hard linking fails?

I tried this but the restrictive permissions (no w) that Bazel has on the built binaries confuse things. For example after I dev build short if I try to rm cockroach then I get the following message:

cockroach$ rm cockroach
override r-xr-xr-x  ricky/wheel for cockroach? y

Makes sense u_u Unfortunate, but I'm happy with this! :)

[rickystewart]

TFTR!

bors r=mari-crl

[craig]

Build succeeded:

• GitHub CI (Cockroach)