diff --git a/pkgs/development/libraries/phonon-backend-gstreamer/qt5/default.nix b/pkgs/development/libraries/phonon-backend-gstreamer/qt5/default.nix
index 2c6e40eaf73..9866c0a67ce 100644
--- a/pkgs/development/libraries/phonon-backend-gstreamer/qt5/default.nix
+++ b/pkgs/development/libraries/phonon-backend-gstreamer/qt5/default.nix
@@ -17,6 +17,11 @@ stdenv.mkDerivation rec {
 
   buildInputs = with gst_all_1; [ gstreamer gst-plugins-base phonon qtbase ];
 
+  NIX_CFLAGS_COMPILE = [
+    # This flag should be picked up through pkgconfig, but it isn't.
+    "-I${gst_all_1.gstreamer}/lib/gstreamer-1.0/include"
+  ];
+
   nativeBuildInputs = [ cmake pkgconfig ];
 
   cmakeFlags = [
diff --git a/pkgs/development/libraries/phonon-backend-gstreamer/qt5/old.nix b/pkgs/development/libraries/phonon-backend-gstreamer/qt5/old.nix
index bc34d249b46..d91808ec880 100644
--- a/pkgs/development/libraries/phonon-backend-gstreamer/qt5/old.nix
+++ b/pkgs/development/libraries/phonon-backend-gstreamer/qt5/old.nix
@@ -15,7 +15,14 @@ stdenv.mkDerivation rec {
     sha256 = "1q1ix6zsfnh6gfnpmwp67s376m7g7ahpjl1qp2fqakzb5cgzgq10";
   };
 
-  buildInputs = with gst_all_1; [ gstreamer gst-plugins-base phonon_qt5 qt5.base ];
+  buildInputs = with gst_all_1; [
+    gstreamer gst-plugins-base phonon_qt5 qt5.base
+  ];
+
+  NIX_CFLAGS_COMPILE = [
+    # This flag should be picked up through pkgconfig, but it isn't.
+    "-I${gst_all_1.gstreamer}/lib/gstreamer-1.0/include"
+  ];
 
   nativeBuildInputs = [ cmake pkgconfig ];