Make './autogen.sh' switch to the top source directory.

.ci/bb/breeze-mpim/test.all.nv-21.3.0

.ci/bb/daint-cscs/test.all.cray-11.0.0

.ci/bb/daint-cscs/test.all.pgi-20.1.1

.ci/bb/mistral-dkrz/test.all.gcc-6.4.0

.ci/bb/mistral-dkrz/test.all.intel-17.0.6

.ci/bb/mistral-dkrz/test.all.nag-6.2.6223

.ci/bb/mistral-dkrz/test.all.pgi-19.9.0

.ci/bb/mistral-dkrz/test.icon-pio.nag-6.2.6223

.ci/bb/mistral-dkrz/test.icon.gcc-6.4.0

autogen.sh