Fix a wrong lineno in backtrace for cfunc

lineno is an int, and INT2FIX(0) was assigned.

[Bug #15719] [ruby-core:91911]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67326 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_backtrace.rb

@@ -329,4 +329,18 @@ class TestBacktrace < Test::Unit::TestCase
     bar
     end;
   end
+
+  def test_caller_to_enum
+    err = ["-:3:in `foo': unhandled exception", "\tfrom -:in `each'"]
+    assert_in_out_err([], <<-"end;", [], err, "[ruby-core:91911]")
+      def foo
+        return to_enum(__method__) unless block_given?
+        raise
+        yield 1
+      end
+
+      enum = foo
+      enum.next
+    end;
+  end
 end

vm_backtrace.c

@@ -352,7 +352,7 @@ location_to_str(rb_backtrace_location_t *loc)
 	}
 	else {
 	    file = GET_VM()->progname;
-	    lineno = INT2FIX(0);
+	    lineno = 0;
 	}
 	name = rb_id2str(loc->body.cfunc.mid);
 	break;