Ignores generated *.elc files in git submodules.

* When cython.git is included as a submodule in an
  Emacs configuration to load cython-mode.el and is
  byte-compiled, it generates an .elc file which causes
  the submodule to appear dirty unnecessarily in the parent
  git repository. Adding this rule will avoid dirty submodules.
Signed-off-by: Yesudeep Mangalapilly <yesudeep@google.com>

.gitignore

@@ -8,6 +8,8 @@ Cython/Compiler/*.c
 Cython/Plex/*.c
 Cython/Runtime/refnanny.c
 
+Tools/*.elc
+
 BUILD/
 build/
 !tests/build/