Clarify that object-properties cannot be reliably applied to numbers.

* doc/ref/api-utility.texi (Object Properties)[make-object-property]:
  Clarify that object-properties cannot be reliably applied to numbers.

Signed-off-by: David Kastrup <dak@gnu.org>
doc: "!#" does not need to appear on a line of its own.

* doc/ref/api-evaluation.texi (Block Comments): Remove "which must appear on a
  line of their own".  Reported by David Michael <fedora.dm0@gmail.com>.
Make temporary file in coding.test work on MS-Windows.

* test-suite/tests/coding.test (with-temp-file): Instead of
  hard-coding "/tmp" as the temporary directory, use $TMPDIR or
  $TEMP from the environment, and fall back on "/tmp" if none of
  those 2 is defined.
Copy the result from 'nl_langinfo' before it can be overwritten.

Based on a patch by Eli Zaretskii <eliz@gnu.org>.

* libguile/i18n.c (copy_string_or_null): New static function.
  (scm_nl_langinfo): Use 'copy_string_or_null' to copy the result from
  'nl_langinfo' and 'nl_langinfo_l' before the next call and before
  releasing the locale mutex.
On MS-Windows, don't return file names with backslashes from search-path.

* libguile/load.c (search_path): On MS-Windows, convert all
  backslashes to forward slashes if the file was found on PATH.