diff --git a/pkgs/development/libraries/qt-5/5.5/qtbase/default.nix b/pkgs/development/libraries/qt-5/5.5/qtbase/default.nix
index 87fb3f08e2b..c4e7689efa2 100644
--- a/pkgs/development/libraries/qt-5/5.5/qtbase/default.nix
+++ b/pkgs/development/libraries/qt-5/5.5/qtbase/default.nix
@@ -269,9 +269,12 @@ stdenv.mkDerivation {
               done
           popd
       fi
+    ''
 
-      # fixup .pc file (where to find 'moc' etc.)
-      sed "s|^host_bins=.*|host_bins=$dev/bin|" -i "$dev/lib/pkgconfig/Qt5Core.pc"
+    # fixup .pc file (where to find 'moc' etc.)
+    + lib.optionalString (!stdenv.isDarwin) ''
+      sed -i "$dev/lib/pkgconfig/Qt5Core.pc" \
+          -e "/^host_bins=/ c host_bins=$dev/bin"
     '';
 
   inherit lndir;
diff --git a/pkgs/development/libraries/qt-5/5.6/qtbase/default.nix b/pkgs/development/libraries/qt-5/5.6/qtbase/default.nix
index 7a80d63356a..60a3896abaf 100644
--- a/pkgs/development/libraries/qt-5/5.6/qtbase/default.nix
+++ b/pkgs/development/libraries/qt-5/5.6/qtbase/default.nix
@@ -272,7 +272,7 @@ stdenv.mkDerivation {
     # fixup .pc file (where to find 'moc' etc.)
     + lib.optionalString (!stdenv.isDarwin) ''
       sed -i "$dev/lib/pkgconfig/Qt5Core.pc" \
-          "s|^host_bins=.*|host_bins=$dev/bin|"
+          -e "/^host_bins=/ c host_bins=$dev/bin"
     ''
 
     # Don't move .prl files on darwin because they end up in
diff --git a/pkgs/development/libraries/qt-5/5.7/qtbase/default.nix b/pkgs/development/libraries/qt-5/5.7/qtbase/default.nix
index 8829b33acf6..73df6726f4a 100644
--- a/pkgs/development/libraries/qt-5/5.7/qtbase/default.nix
+++ b/pkgs/development/libraries/qt-5/5.7/qtbase/default.nix
@@ -233,7 +233,7 @@ stdenv.mkDerivation {
     # fixup .pc file (where to find 'moc' etc.)
     + lib.optionalString (!stdenv.isDarwin) ''
       sed -i "$dev/lib/pkgconfig/Qt5Core.pc" \
-          "s|^host_bins=.*|host_bins=$dev/bin|"
+          -e "/^host_bins=/ c host_bins=$dev/bin"
     ''
 
     # Don't move .prl files on darwin because they end up in
diff --git a/pkgs/development/libraries/qt-5/5.8/qtbase/default.nix b/pkgs/development/libraries/qt-5/5.8/qtbase/default.nix
index e6d8b5ffeea..a48c5dbb07a 100644
--- a/pkgs/development/libraries/qt-5/5.8/qtbase/default.nix
+++ b/pkgs/development/libraries/qt-5/5.8/qtbase/default.nix
@@ -230,7 +230,7 @@ stdenv.mkDerivation {
     # fixup .pc file (where to find 'moc' etc.)
     + lib.optionalString (!stdenv.isDarwin) ''
       sed -i "$dev/lib/pkgconfig/Qt5Core.pc" \
-          "s|^host_bins=.*|host_bins=$dev/bin|"
+          -e "/^host_bins=/ c host_bins=$dev/bin"
     ''
 
     # Don't move .prl files on darwin because they end up in