Apparently our Tags field depended on having specific files react to
tags and add themselves there. This, instead, works for all tags.
Also, pass tags to the test command line.
This adds some env vars to the long version string as if they were build
tags. The purpose is to better understand what code was running or not
in the version output, usage reporting and crash reports. In order to
prevent possible privacy issues the actual value of the variable is not
reported, just the fact that it was set to something non-empty.
Example:
% ./bin/syncthing --version
syncthing v1.6.1+47-g1eb104f3-buildtags "Fermium Flea" (go1.14.3 darwin-amd64) jb@kvin.kastelo.net 2020-06-03 07:25:46 UTC [stnoupgrade, use_badger]
This changes the build script to build all the things in one go
invocation, instead of one invocation per cmd. This is a lot faster
because it means more things get compiled concurrently. It's especially
a lot faster when things *don't* need to be rebuilt, possibly because it
only needs to build the dependency map and such once instead of once per
binary.
In order for this to work we need to be able to pass the same ldflags to
all the binaries. This means we can't set the program name with an
ldflag.
When it needs to rebuild everything (go clean -cache):
( ./old-build -gocmd go1.14.2 build all 2> /dev/null; ) 65.82s user 11.28s system 574% cpu 13.409 total
( ./new-build -gocmd go1.14.2 build all 2> /dev/null; ) 63.26s user 7.12s system 1220% cpu 5.766 total
On a subsequent run (nothing to build, just link the binaries):
( ./old-build -gocmd go1.14.2 build all 2> /dev/null; ) 26.58s user 7.53s system 582% cpu 5.853 total
( ./new-build -gocmd go1.14.2 build all 2> /dev/null; ) 18.66s user 2.45s system 1090% cpu 1.935 total
The relay and discosrv didn't use the new lib/build package, now they
do. Conversely the lib/build package wasn't aware there might be other
users and hard coded the program name - now it's set by the build
script
