[LyX/master] Fix Qt4 compilation.

[Pavel Sanda]

commit 28dd0e1f21e620b1ee13340a4c9b6beeb56abc8a
Author: Pavel Sanda <sanda at lyx.org>
Date:   Thu Aug 27 14:05:22 2020 +0200

    Fix Qt4 compilation.
---
 src/frontends/qt/qt_helpers.cpp |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/frontends/qt/qt_helpers.cpp b/src/frontends/qt/qt_helpers.cpp
index 87b6593..2e5e7da 100644
--- a/src/frontends/qt/qt_helpers.cpp
+++ b/src/frontends/qt/qt_helpers.cpp
@@ -292,14 +292,14 @@ void showDirectory(FileName const & directory)
 	if (!qurl.isValid()) {
 		frontend::Alert::error(_("Invalid URL"),
 			bformat(_("The URL `%1$s' could not be resolved."),
-				qstring_to_ucs4(qurl.url())));
+				qstring_to_ucs4(qurl.toString())));
 		return;
 
 	}
 	if (!QDesktopServices::openUrl(qurl))
 		frontend::Alert::error(_("URL could not be accessed"),
 			bformat(_("The URL `%1$s' could not be opened although it exists!"),
-				qstring_to_ucs4(qurl.url())));
+				qstring_to_ucs4(qurl.toString())));
 }
 
 void showTarget(string const & target, string const & pdfv, string const & psv)