Fix small source-map regression

Author: mgreter

debugger.hpp

@@ -344,7 +344,8 @@ inline void debug_ast(AST_Node* node, string ind = "", Env* env = 0)
     cerr << " (" << pstate_source_position(node) << ")";
     cerr << " [name: " << block->name() << "] ";
     cerr << " [type: " << (block->type() == Sass::Definition::Type::MIXIN ? "Mixin " : "Function ") << "] ";
-    cerr << " [signature: " << block->signature() << "] ";
+    // this seems to lead to segfaults some times?
+    // cerr << " [signature: " << block->signature() << "] ";
     cerr << " [native: " << block->native_function() << "] ";
     cerr << " " << block->tabs() << endl;
     debug_ast(block->parameters(), ind + " params: ", env);

parser.cpp

@@ -1619,8 +1619,9 @@ namespace Sass {
   {
     lex< identifier >();
     string name(lexed);
+    ParserState call_pos = pstate;
     Arguments* args = parse_arguments(name == "url");
-    return new (ctx.mem) Function_Call(pstate, name, args);
+    return new (ctx.mem) Function_Call(call_pos, name, args);
   }
 
   Function_Call_Schema* Parser::parse_function_call_schema()