build: fix regressions with the -dlgo change (#21831)

This fixes cross-build and mobile framework failures.
It also disables the mac test builder because it was failing
all the time in hard to understand ways and we can't afford
it anymore under Travis CI's new pricing.
# Conflicts:
#	build/ci.go

.travis.yml

@@ -55,24 +55,6 @@ jobs:
       script:
         - go run build/ci.go test -coverage $TEST_PACKAGES
 
-    - stage: build
-      os: osx
-      osx_image: xcode11.3
-      go: 1.15.x
-      env:
-        - GO111MODULE=on
-      script:
-        - echo "Increase the maximum number of open file descriptors on macOS"
-        - NOFILE=20480
-        - sudo sysctl -w kern.maxfiles=$NOFILE
-        - sudo sysctl -w kern.maxfilesperproc=$NOFILE
-        - sudo launchctl limit maxfiles $NOFILE $NOFILE
-        - sudo launchctl limit maxfiles
-        - ulimit -S -n $NOFILE
-        - ulimit -n
-        - unset -f cd # workaround for https://github.com/travis-ci/travis-ci/issues/8703
-        - go run build/ci.go test -coverage $TEST_PACKAGES
-
     # This builder does the Ubuntu PPA upload
     - stage: build
       if: type = push