tool_doswin: Improve sanitization processing

- Add unit test 1604 to test the sanitize_file_name function.

- Use -DCURL_STATICLIB when building libcurltool for unit testing.

- Better detection of reserved DOS device names.

- New flags to modify sanitize behavior:

SANITIZE_ALLOW_COLONS: Allow colons
SANITIZE_ALLOW_PATH: Allow path separators and colons
SANITIZE_ALLOW_RESERVED: Allow reserved device names
SANITIZE_ALLOW_TRUNCATE: Allow truncating a long filename

- Restore sanitization of banned characters from user-specified outfile.

Prior to this commit sanitization of a user-specified outfile was
temporarily disabled in 2b6dadc because there was no way to allow path
separators and colons through while replacing other banned characters.
Now in such a case we call the sanitize function with
SANITIZE_ALLOW_PATH which allows path separators and colons to pass
through.


Closes https://github.com/curl/curl/issues/624
Reported-by: Octavio Schroeder

src/tool_operate.c

@@ -543,15 +543,6 @@ static CURLcode operate_do(struct GlobalConfig *global,
             result = get_url_file_name(&outfile, this_url);
             if(result)
               goto show_error;
-
-#if defined(MSDOS) || defined(WIN32)
-            result = sanitize_file_name(&outfile);
-            if(result) {
-              Curl_safefree(outfile);
-              goto show_error;
-            }
-#endif /* MSDOS || WIN32 */
-
             if(!*outfile && !config->content_disposition) {
               helpf(global->errors, "Remote file name has no length!\n");
               result = CURLE_WRITE_ERROR;