automatic setup of prefix and build dir in ~/.autoprojrc

autoprojrc_automatic_split_of_prefix_and_build.rb

# This code automatically splits prefix and build folders
# to match the directory layout under a root dev directory
#
# It is meant to be added in ~/.autoprojrc
#
# The autoproj bootstrap under #{dev_dir}/vanilla/rock-core
# will have its prefix in
#    #{build_dir}/vanilla/rock-core/install
#
# and each package will have its build directory in
#    #{build_dir}/vanilla/rock-core/name/of/package

dev_dir = File.join(Dir.home, 'dev')
if Autoproj.workspace.root_dir.start_with?(dev_dir + "/")
    workspace_name = Pathname.new(Autoproj.workspace.root_dir).
        relative_path_from(Pathname.new(dev_dir)).to_s
    Autoproj.workspace.prefix_dir = File.join(dev_dir, 'build_area', workspace_name, 'install')
    Autoproj.workspace.build_dir = File.join(dev_dir, 'build_area', workspace_name)
end