ENH: Add TCL_FOUND

Modules/FindTCL.cmake

@@ -176,3 +176,13 @@ MARK_AS_ADVANCED(
   TK_STUB_LIBRARY  
   TK_STUB_LIBRARY_DEBUG
   )
+
+IF(TCL_INCLUDE_PATH)
+  IF(TK_INCLUDE_PATH)
+    IF(TCL_LIBRARY)
+      IF(TK_LIBRARY)
+        SET(TCL_FOUND 1)
+      ENDIF(TK_LIBRARY)
+    ENDIF(TCL_LIBRARY)
+  ENDIF(TK_INCLUDE_PATH)
+ENDIF(TCL_INCLUDE_PATH)