depends: Backport Qt bugfixes

Dogecoin-Qt cannot upgrade Qt on a minor release without breaking
support for older systems, and thus preventing operators on these
to get important security updates. Therefore, it is important to
patch the fixed version of Qt we are stuck with when applicable.

This backports important bug fixes from later Qt versions that
harden Dogecoin-Qt's internals:

- Fix possible heap corruption in QXmlStream
  see: https://codereview.qt-project.org/c/qt/qtbase/+/236691

- do not attempt to load a library relative to $PWD
  see: https://codereview.qt-project.org/c/qt/qtbase/+/286795

- Fix specific overflow in qtextlayout
  see: https://codereview.qt-project.org/c/qt/qtbase/+/476125

- QDnsLookup/Unix: Ensure that both the RDATA and the Record header
  fields before it fall inside the buffer we have
  see: https://codereview.qt-project.org/c/qt/qtbase/+/477644

- Fix a crash while parsing an XML file with garbage data
  see: https://codereview.qt-project.org/c/qt/qtbase/+/471756
       https://codereview.qt-project.org/c/qt/qtbase/+/455027

- Fix crash when reading corrupt font data
  see: https://codereview.qt-project.org/c/qt/qtbase/+/503026

depends/packages/qt.mk

@@ -16,6 +16,7 @@ $(package)_patches+=fix-xcb-include-order.patch
 $(package)_patches+=fix_qfontengine_coretext.patch
 $(package)_patches+=fix_qt_pkgconfig.patch
 $(package)_patches+=no-xlib.patch
+$(package)_patches+=backports-1.patch
 
 $(package)_qttranslations_file_name=qttranslations-$($(package)_suffix)
 $(package)_qttranslations_sha256_hash=3a15aebd523c6d89fb97b2d3df866c94149653a26d27a00aac9b6d3020bc5a1d
@@ -182,6 +183,7 @@ define $(package)_preprocess_cmds
   patch -p1 < $($(package)_patch_dir)/fix_qfontengine_coretext.patch && \
   patch -p1 < $($(package)_patch_dir)/fix_qt_pkgconfig.patch && \
   patch -p1 -i $($(package)_patch_dir)/no-xlib.patch && \
+  patch -p1 < $($(package)_patch_dir)/backports-1.patch && \
   echo "!host_build: QMAKE_CFLAGS     += $($(package)_cflags) $($(package)_cppflags)" >> qtbase/mkspecs/common/gcc-base.conf && \
   echo "!host_build: QMAKE_CXXFLAGS   += $($(package)_cxxflags) $($(package)_cppflags)" >> qtbase/mkspecs/common/gcc-base.conf && \
   echo "!host_build: QMAKE_LFLAGS     += $($(package)_ldflags)" >> qtbase/mkspecs/common/gcc-base.conf && \