[LyX/master] Apple has builtin native spell checker, no need to warn for missing Aspell, hunspell or Enchant

[Stephan Witt]

commit e67e37d7590c16297686ff426497db8feaefcdbe
Author: Stephan Witt <sw...@lyx.org>
Date:   Thu Jun 12 14:55:56 2014 +0200

    Apple has builtin native spell checker, no need to warn for missing Aspell, 
hunspell or Enchant

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3bc9228..032b47f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -866,7 +866,7 @@ if(LYX_NLS)
        message(STATUS)
 endif()
 
-if(NOT Spelling_FOUND)
+if(NOT Spelling_FOUND AND NOT APPLE)
   if(LYX_REQUIRE_SPELLCHECK)
     set(_mode "FATAL_ERROR")
   else()