`add_subdirectory` Common instead of include

It was difficult to find the `CMakeLists.txt` that controlled the the
compilation of a given file from the message of a compilation error.

CMakeLists.txt

@@ -37,4 +37,5 @@ else()
 endif()
 
 include(Tests/CMakeLists.txt)
+add_subdirectory(Common)
 include(TAGS)

Common/CMakeLists.txt

+target_sources(test_get_1_outerm PRIVATE derived_types.f90
+  spher_polyline_area.f90 shpc_create.f90 write_eddy.f90
+  shpc_close.f90)
+
+target_sources(test_set_all_outerm PRIVATE derived_types.f90
+  spher_polyline_area.f90 shpc_create.f90 write_eddy.f90
+  shpc_close.f90)
+
+target_sources(test_max_speed_contour_ssh PRIVATE derived_types.f90 )
+
+target_sources(test_nearby_extr PRIVATE derived_types.f90
+  read_snapshot.f90 read_eddy.f90 read_field_indices.F90 shpc_open.F90
+  shpc_close.f90)
+
+target_sources(test_set_max_speed PRIVATE derived_types.f90
+  spher_polyline_area.f90 shpc_open.F90 shpc_close.f90
+  read_field_indices.F90 read_eddy.f90 shpc_create.f90 write_eddy.f90)

Inst_eddies/Tests/CMakeLists.txt

 # test_get_1_outerm
 
-add_executable(test_get_1_outerm
-  ${PROJECT_SOURCE_DIR}/Common/derived_types.f90
-  ${PROJECT_SOURCE_DIR}/Common/spher_polyline_area.f90
-  test_get_1_outerm.f90
-  ${PROJECT_SOURCE_DIR}/Common/shpc_create.f90
-  ${PROJECT_SOURCE_DIR}/Common/write_eddy.f90
-  ${PROJECT_SOURCE_DIR}/Common/shpc_close.f90)
+add_executable(test_get_1_outerm test_get_1_outerm.f90 )
 
 target_link_libraries(test_get_1_outerm Geometry::geometry
   NetCDF95::netcdf95 Shapelib_03::shapelib_03 Contour_531::contour_531
@@ -14,13 +8,7 @@ target_link_libraries(test_get_1_outerm Geometry::geometry
 
 # test_set_all_outerm
 
-add_executable(test_set_all_outerm
-  ${PROJECT_SOURCE_DIR}/Common/derived_types.f90
-  ${PROJECT_SOURCE_DIR}/Common/spher_polyline_area.f90
-  test_set_all_outerm.f90
-  ${PROJECT_SOURCE_DIR}/Common/shpc_create.f90
-  ${PROJECT_SOURCE_DIR}/Common/write_eddy.f90
-  ${PROJECT_SOURCE_DIR}/Common/shpc_close.f90)
+add_executable(test_set_all_outerm test_set_all_outerm.f90)
 
 target_link_libraries(test_set_all_outerm PRIVATE Geometry::geometry
   NetCDF95::netcdf95 Numer_Rec_95::numer_rec_95
@@ -56,7 +44,6 @@ target_link_libraries(test_mean_speed Numer_Rec_95::numer_rec_95
 # test_max_speed_contour_ssh
 
 add_executable(test_max_speed_contour_ssh
-  ${PROJECT_SOURCE_DIR}/Common/derived_types.f90
   test_max_speed_contour_ssh.f90)
 
 target_link_libraries(test_max_speed_contour_ssh PRIVATE
@@ -65,14 +52,7 @@ target_link_libraries(test_max_speed_contour_ssh PRIVATE
 
 # test_nearby_extr
 
-add_executable(test_nearby_extr
-  ${PROJECT_SOURCE_DIR}/Common/derived_types.f90
-  test_nearby_extr.f90
-  ${PROJECT_SOURCE_DIR}/Common/read_snapshot.f90
-  ${PROJECT_SOURCE_DIR}/Common/read_eddy.f90
-  ${PROJECT_SOURCE_DIR}/Common/read_field_indices.F90
-  ${PROJECT_SOURCE_DIR}/Common/shpc_open.F90
-  ${PROJECT_SOURCE_DIR}/Common/shpc_close.f90)
+add_executable(test_nearby_extr test_nearby_extr.f90)
 
 target_link_libraries(test_nearby_extr Shapelib_03::shapelib_03
   Contour_531::contour_531 Jumble::jumble gpc_f)
@@ -88,16 +68,7 @@ target_link_libraries(test_local_extrema NetCDF95::netcdf95
 
 # test_set_max_speed
 
-add_executable(test_set_max_speed
-  ${PROJECT_SOURCE_DIR}/Common/derived_types.f90
-  ${PROJECT_SOURCE_DIR}/Common/spher_polyline_area.f90
-  test_set_max_speed.f90
-  ${PROJECT_SOURCE_DIR}/Common/shpc_open.F90
-  ${PROJECT_SOURCE_DIR}/Common/shpc_close.f90
-  ${PROJECT_SOURCE_DIR}/Common/read_field_indices.F90
-  ${PROJECT_SOURCE_DIR}/Common/read_eddy.f90
-  ${PROJECT_SOURCE_DIR}/Common/shpc_create.f90
-  ${PROJECT_SOURCE_DIR}/Common/write_eddy.f90)
+add_executable(test_set_max_speed test_set_max_speed.f90)
 
 target_link_libraries(test_set_max_speed Geometry::geometry
   Numer_Rec_95::numer_rec_95 NetCDF95::netcdf95