h5attr read: remove unused param H5S_ALL_F

this unused parameter caused problems for GCC-7 recognizing TKR.

Making the arguments optional caused problems with all compilers
recognizing TKR

src/attr_read.f90

@@ -1,11 +1,6 @@
 submodule (h5fortran:attr_smod) attr_read
 
-use, intrinsic :: iso_c_binding, only : C_CHAR, C_NULL_CHAR, C_F_POINTER
-
-use hdf5, only : H5Aread_f, H5Aget_type_f, &
-H5Tget_class_f, H5Tget_native_type_f, H5Tget_size_f, H5Tget_strpad_f, &
-H5T_DIR_ASCEND_F, &
-H5S_ALL_F
+use hdf5, only : H5Aread_f
 
 implicit none
 

src/attr_read.inc

@@ -38,7 +38,9 @@ if(attr_class == H5T_FLOAT_F .OR. attr_class == H5T_INTEGER_F) then
 elseif(attr_class == H5T_STRING_F) then
   select type(A)
   type is (character(*)) !< kind=c_char too
-    call read_char(self, obj_name//":"//attr_name, A, attr_id, H5S_ALL_F, space_id)
+    call read_char(self, obj_name//":"//attr_name, A, attr_id, 0_HID_T, space_id)
+    !! the "0_HID_T" is unused by H5Aread_F. GCC 7 doesn't like H5S_ALL_F, and it's unused anyway
+    !! making this argument optional in read_char() caused problems with all compilers recognizing the TKR
   class default
     error stop 'ERROR:h5fortran:readattr: string dataset ' // obj_name // ':' // attr_name // ' needs character memory variable'
   end select