qt55.qtbase: upstream patch for backing store issue

The included patch from upstream fixes the issue described here:
https://bugreports.qt.io/browse/QTBUG-48321
The backing store of certain widgets was being improperly invalidated,
leading to display bugs in, e.g. VLC.

This patch is included in Qt 5.6, so we should remove it when we
upgrade.

+10
+10
pkgs/development/libraries/qt-5/5.5/qtbase/default.nix
··· 26 let 27 inherit (srcs.qt5) version; 28 system-x86_64 = lib.elem stdenv.system lib.platforms.x86_64; 29 in 30 31 stdenv.mkDerivation { ··· 49 50 postPatch = 51 '' 52 substituteInPlace configure --replace /bin/pwd pwd 53 substituteInPlace qtbase/configure --replace /bin/pwd pwd 54 substituteInPlace qtbase/src/corelib/global/global.pri --replace /bin/ls ${coreutils}/bin/ls
··· 26 let 27 inherit (srcs.qt5) version; 28 system-x86_64 = lib.elem stdenv.system lib.platforms.x86_64; 29 + 30 + dontInvalidateBacking = fetchurl { 31 + url = "https://codereview.qt-project.org/gitweb?p=qt/qtbase.git;a=patch;h=0f68f8920573cdce1729a285a92ac8582df32841;hp=24c50f8dcf7fa61ac3c3d4d6295c259a104a2b8c"; 32 + name = "qtbug-48321-dont-invalidate-backing-store.patch"; 33 + sha256 = "07vnndmvri73psz0nrs2hg0zw2i4b1k1igy2al6kwjbp7d5xpglr"; 34 + }; 35 in 36 37 stdenv.mkDerivation { ··· 55 56 postPatch = 57 '' 58 + cd qtbase 59 + patch -p1 <${dontInvalidateBacking} 60 + cd .. 61 + 62 substituteInPlace configure --replace /bin/pwd pwd 63 substituteInPlace qtbase/configure --replace /bin/pwd pwd 64 substituteInPlace qtbase/src/corelib/global/global.pri --replace /bin/ls ${coreutils}/bin/ls