Allow c_support_code() to return a string or a list of strings

theano/gof/cc.py

@@ -914,7 +914,11 @@ class CLinker(link.Linker):
         for x in [y.type for y in self.variables] + [
                 y.op for y in self.node_order]:
             try:
-                ret.append(x.c_support_code())
+                support_code = x.c_support_code()
+                if isinstance(support_code, list):
+                    ret.extend(support_code)
+                else:
+                    ret.append(support_code)
             except utils.MethodNotDefined:
                 pass
         return ret