(FIXUP) always source sage-env
Fix install script for gcc
Revert "(FIXUP) always source sage-env"

This reverts commit 43e5bfda79eb8258fe73e040f20ec206b8a96d03.
fix cython long doctests
always source sage-env during the build process
make sure we only bootstrap emerge when necessary (2)
Merge remote-tracking branch 'sagemath/master' into lmonade