gitignore: clang creates a lot of *.tmp files

Also sort the list of extensions.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>

.gitignore

@@ -1,7 +1,8 @@
 *.[ao]
 *.bak
-*.new
 *.dep
+*.new
+*.tmp
 *.so*
 Doxyfile
 README.html