Fix compilation of D8 with console=readline

src/d8-readline.cc

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 12 matching lines @@
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
 #include <cstdio>  // NOLINT
 #include <readline/readline.h> // NOLINT
 #include <readline/history.h> // NOLINT
 
+// The readline includes leaves RETURN defined which breaks V8 compilation.
+#undef RETURN
 
 #include "d8.h"
 
 
 // There are incompatibilities between different versions and different
 // implementations of readline.  This smooths out one known incompatibility.
 #if RL_READLINE_VERSION >= 0x0500
 #define completion_matches rl_completion_matches
 #endif
 
@@ skipping 76 matching lines @@
     return strdup(*str);
   } else {
     current_completions.Dispose();
     current_completions.Clear();
     return NULL;
   }
 }
 
 
 }  // namespace v8