Bug fix: avoid aliases in arguments

Define two variables `hshp_in` and `hshp_out` to avoid aliases in
arguments of `shpc_create`. I have encountered a run which crashed there.

Overlap/Tests/test_read_eddy.f90

@@ -15,7 +15,7 @@ program test_read_eddy
   type(eddy) e
   integer k, eddy_i
   integer:: ishape = 0
-  TYPE(shpc_slice_handler) hshp
+  TYPE(shpc_slice_handler) hshp_in, hshp_out
   character(len = :), allocatable:: shpc_dir
   namelist /main_nml/ ishape
 
@@ -24,13 +24,13 @@ program test_read_eddy
   call get_command_arg_dyn(1, shpc_dir, "Required argument: SHPC-directory")
   print *, "Enter namelist main_nml."
   read(unit = *, nml = main_nml)
-  call shpc_open(hshp, shpc_dir, pszaccess = "rb")
-  call read_eddy(e, k, eddy_i, hshp, ishape)
-  CALL shpc_close(hshp)
+  call shpc_open(hshp_in, shpc_dir, pszaccess = "rb")
+  call read_eddy(e, k, eddy_i, hshp_in, ishape)
+  CALL shpc_close(hshp_in)
 
-  call shpc_create(hshp, shpc_dir = "SHPC", cyclone = hshp%cyclone)
-  call write_eddy(e, hshp, k, eddy_i)
-  CALL shpc_close(hshp)
+  call shpc_create(hshp_out, shpc_dir = "SHPC", cyclone = hshp_in%cyclone)
+  call write_eddy(e, hshp_out, k, eddy_i)
+  CALL shpc_close(hshp_out)
   print *, 'Created shapefiles in SHPC.'
 
 end program test_read_eddy