Compilation failure in flang

[liamh]

When compiling 9ac7bf7 with AOCC flang 4.0.0,

fpm build --compiler flang
string_module.f90                      done.
kind_module.f90                        done.
base_class_module.f90                  done.
complex_step.f90                       done.
numbers_module.f90                     done.
drag_module.f90                        done.
random_module.f90                      done.
geodesy_module.f90                     done.
matrix_module.f90                      done.
eispack_module.f90                     done.
gravity_module.f90                     done.
gooding_module.f90                     done.
celestial_body_module.f90              failed.
[ 30%] Compiling...
F90-F-0155-No default initialization in structure constructor- member ==$4 (./src/celestial_body_module.f90: 23)
F90/x86-64 Linux Flang - 1.5 2017-05-01: compilation aborted
<ERROR> Compilation failed for object " src_celestial_body_module.f90.o "
<ERROR>stopping due to failed compilation
STOP 1