gnu: qtwayland: Fix build with GCC 11.

* gnu/packages/patches/qtwayland-gcc-11.patch: New file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/qt.scm (qtwayland)[source](patches): New field.

gnu/local.mk

@@ -1750,6 +1750,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/qtscript-disable-tests.patch		\
   %D%/packages/patches/quagga-reproducible-build.patch          \
   %D%/packages/patches/quickswitch-fix-dmenu-check.patch	\
+  %D%/packages/patches/qtwayland-gcc-11.patch			\
   %D%/packages/patches/qtwebkit-pbutils-include.patch		\
   %D%/packages/patches/qtwebkit-fix-building-with-bison-3.7.patch \
   %D%/packages/patches/qtwebkit-fix-building-with-python-3.9.patch	\

gnu/packages/patches/qtwayland-gcc-11.patch

@@ -0,0 +1,18 @@
+Add missing import for newer libstdc++.
+
+Taken from upstream:
+
+  https://github.com/qt/qtwayland/commit/1aa6ec2c778504d96543f6cdc2b9199a7b066fc1
+
+diff --git a/tests/auto/client/shared/corecompositor.cpp b/tests/auto/client/shared/corecompositor.cpp
+index 5c6c83baa..fa9b7662a 100644
+--- a/tests/auto/client/shared/corecompositor.cpp
++++ b/tests/auto/client/shared/corecompositor.cpp
+@@ -27,6 +27,7 @@
+ ****************************************************************************/
+ 
+ #include "corecompositor.h"
++#include <thread>
+ 
+ namespace MockCompositor {
+ 

gnu/packages/qt.scm

@@ -1456,6 +1456,7 @@ set of plugins for interacting with pulseaudio and GStreamer.")
     (source (origin
              (method url-fetch)
              (uri (qt5-urls name version))
+             (patches (search-patches "qtwayland-gcc-11.patch"))
              (sha256
               (base32
                "1ddfx4nak16xx0zh1kl836zxvpbixmmjyplsmfmg65pqkwi34dqr"))))