env GO111MODULE=off

# If GOTMPDIR is relative, 'go build' should derive an absolute $WORK directory.
cd $WORK
mkdir tmp
env GOTMPDIR=tmp
go build -work a
stderr 'WORK='$WORK

# Similarly if TMP/TMPDIR is relative.
env GOTMPDIR=
env TMP=tmp    # Windows
env TMPDIR=tmp # Unix
go build -work a
stderr 'WORK='$WORK

-- a/a.go --
package a
