diff --git a/pkgs/development/libraries/qt-4.x/4.8/clang-5-darwin.patch b/pkgs/development/libraries/qt-4.x/4.8/clang-5-darwin.patch
new file mode 100644
index 00000000000..7b181f3ad89
--- /dev/null
+++ b/pkgs/development/libraries/qt-4.x/4.8/clang-5-darwin.patch
@@ -0,0 +1,13 @@
+diff --git a/src/gui/text/qfontengine_coretext.mm b/src/gui/text/qfontengine_coretext.mm
+index 204d685..e05179e 100644
+--- a/src/gui/text/qfontengine_coretext.mm
++++ b/src/gui/text/qfontengine_coretext.mm
+@@ -886,7 +886,7 @@ void QCoreTextFontEngine::getUnscaledGlyph(glyph_t glyph, QPainterPath *path, gl
+ 
+ QFixed QCoreTextFontEngine::emSquareSize() const
+ {
+-    return QFixed::QFixed(int(CTFontGetUnitsPerEm(ctfont)));
++    return QFixed(int(CTFontGetUnitsPerEm(ctfont)));
+ }
+ 
+ QFontEngine *QCoreTextFontEngine::cloneWithSize(qreal pixelSize) const
diff --git a/pkgs/development/libraries/qt-4.x/4.8/default.nix b/pkgs/development/libraries/qt-4.x/4.8/default.nix
index a9bd25ed28b..46f24a08b5e 100644
--- a/pkgs/development/libraries/qt-4.x/4.8/default.nix
+++ b/pkgs/development/libraries/qt-4.x/4.8/default.nix
@@ -68,6 +68,7 @@ stdenv.mkDerivation rec {
     [ ./glib-2.32.patch
       ./libressl.patch
       ./parallel-configure.patch
+      ./clang-5-darwin.patch
       ./qt-4.8.7-unixmake-darwin.patch
       (substituteAll {
         src = ./dlopen-absolute-paths.diff;