compile warnings in nc_test4

[edhartnett]

There are a number of compile warnings in nc_test4.

I will have a PR up shortly with fixes.

renamegroup.c: In function ‘main’:
renamegroup.c:41:9: warning: unused variable ‘i’ [-Wunused-variable]
     int i,stat;
         ^
/

tst_h_strbug.c: In function ‘main’:
tst_h_strbug.c:42:8: warning: unused variable ‘v1dattid’ [-Wunused-variable]
  hid_t v1dattid, v1ddsetid;
        ^~~~~~~~
tst_h_strbug.c:40:8: warning: unused variable ‘class’ [-Wunused-variable]
  hid_t class;
        ^~~~~
tst_h_strbug.c:131:19: warning: unused variable ‘ndims’ [-Wunused-variable]
  int ncid, varid, ndims;
                   ^~~~~
tst_h_strbug.c:131:12: warning: unused variable ‘varid’ [-Wunused-variable]
  int ncid, varid, ndims;
            ^~~~~
tst_h_strbug.c:148:19: warning: unused variable ‘ndims’ [-Wunused-variable]
  int ncid, varid, ndims;
                   ^~~~~
tst_h_strbug.c:148:12: warning: unused variable ‘varid’ [-Wunused-variable]
  int ncid, varid, ndims;
            ^~~~~
tst_h_strbug.c:35:10: warning: unused variable ‘ch’ [-Wunused-variable]
     char ch;
          ^~

tst_rename.c: In function ‘main’:
tst_rename.c:226:22: warning: unused variable ‘att_len’ [-Wunused-variable]
               size_t att_len;
                      ^~~~~~~
tst_rename.c:225:23: warning: unused variable ‘att_type’ [-Wunused-variable]
               nc_type att_type;
                       ^~~~~~~~
tst_rename.c:176:61: warning: unused variable ‘units_att’ [-Wunused-variable]
             int ncid, g1_grp, lon_dim, lon_var, g1_lon_var, units_att;


 tst_h5_endians.c: In function ‘main’:
tst_h5_endians.c:41:7: warning: variable ‘retval’ set but not used [-Wunused-but-set-variable]
   int retval = 0;
       ^~~~~~

tst_hdf5_file_compat.c: In function ‘main’:
tst_hdf5_file_compat.c:36:7: warning: unused variable ‘res’ [-Wunused-variable]
   int res = 0;
       ^~~


tst_fill_attr_vanish.c: In function ‘main’:
tst_fill_attr_vanish.c:50:9: warning: unused variable ‘pfills’ [-Wunused-variable]
   float pfills[] = {3};
         ^~~~~~
tst_fill_attr_vanish.c:49:10: warning: unused variable ‘edg’ [-Wunused-variable]
   size_t edg[RANK_P] = {1, 1, LEN};
          ^~~
tst_fill_attr_vanish.c:48:10: warning: unused variable ‘cor’ [-Wunused-variable]
   size_t cor[RANK_P] = {0, 1, 0};
          ^~~
tst_fill_attr_vanish.c:47:16: warning: unused variable ‘P_data’ [-Wunused-variable]
   static float P_data[LEN];
                ^~~~~~
tst_fill_attr_vanish.c:46:9: warning: unused variable ‘ddata’ [-Wunused-variable]
   float ddata[1][4][3];
         ^~~~~
tst_fill_attr_vanish.c:37:14: warning: unused variable ‘dimids_in’ [-Wunused-variable]
   int ndims, dimids_in[RANK_P];
              ^~~~~~~~~
tst_fill_attr_vanish.c:37:7: warning: unused variable ‘ndims’ [-Wunused-variable]
   int ndims, dimids_in[RANK_P];
       ^~~~~
At top level:
tst_fill_attr_vanish.c:47:16: warning: ‘P_data’ defined but not used [-Wunused-variable]
   static float P_data[LEN];
                ^~~~~~


tst_fill_attr_vanish.c: In function ‘main’:
tst_fill_attr_vanish.c:50:9: warning: unused variable ‘pfills’ [-Wunused-variable]
   float pfills[] = {3};
         ^~~~~~
tst_fill_attr_vanish.c:49:10: warning: unused variable ‘edg’ [-Wunused-variable]
   size_t edg[RANK_P] = {1, 1, LEN};
          ^~~
tst_fill_attr_vanish.c:48:10: warning: unused variable ‘cor’ [-Wunused-variable]
   size_t cor[RANK_P] = {0, 1, 0};
          ^~~
tst_fill_attr_vanish.c:47:16: warning: unused variable ‘P_data’ [-Wunused-variable]
   static float P_data[LEN];
                ^~~~~~
tst_fill_attr_vanish.c:46:9: warning: unused variable ‘ddata’ [-Wunused-variable]
   float ddata[1][4][3];
         ^~~~~
tst_fill_attr_vanish.c:37:14: warning: unused variable ‘dimids_in’ [-Wunused-variable]
   int ndims, dimids_in[RANK_P];
              ^~~~~~~~~
tst_fill_attr_vanish.c:37:7: warning: unused variable ‘ndims’ [-Wunused-variable]
   int ndims, dimids_in[RANK_P];
       ^~~~~
At top level:
tst_fill_attr_vanish.c:47:16: warning: ‘P_data’ defined but not used [-Wunused-variable]
   static float P_data[LEN];
                ^~~~~~


tst_h_strbug.c: In function ‘main’:
tst_h_strbug.c:129:12: warning: unused variable ‘ndims’ [-Wunused-variable]
  int ncid, ndims;
            ^~~~~