remove pure storage support

remove pure storage support

* src/alloc.c (pure, PUREBEG, purebeg, pure_size)
  (pure_bytes_used_before_overflow, PURE_POINTER_P)
  (pure_bytes_used_lisp, pure_bytes_used_non_lisp, ALIGN, pure_alloc)
  (find_string_data_in_pure, make_pure_float, make_pure_vector): Remove.
  All references changed.

  (make_pure_string, make_pure_c_string, pure_cons, make_pure_float):
  Call the corresponding normal allocation function.

  (Fpurecopy): Return the argument.

  (check_pure_size): Make this a no-op.

  (make_empty_string): New function.
  (init_strings): Use `make_empty_string'.

  (valid_lisp_object_p): Simplify.

* src/data.c (pure_write_error): Remove.

* src/puresize.h (CHECK_IMPURE): Make this a no-op.

  (PURE_P): Return false.

  (SYSTEM_PURESIZE_EXTRA, SITELOAD_PURESIZE_EXTRA, BASE_PURESIZE)
  (PURESIZE_RATIO, PURESIZE_CHECKING_RATIO, PURESIZE): Remove.

* configure.in (SYSTEM_PURESIZE_EXTRA): Remove.

Conflicts:
	src/alloc.c
	src/puresize.h