Add dev-qt from an older version of the gentoo repo

Qt5 has been removed, we restore it since we still use it.

dev-qt/qtwebengine/files/qtwebengine-6.8.2-glibc2.41.patch

@@ -0,0 +1,20 @@
+https://bugs.gentoo.org/949654
+https://bugreports.qt.io/browse/QTBUG-134631
+--- a/src/3rdparty/chromium/sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.cc
++++ b/src/3rdparty/chromium/sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.cc
+@@ -36,4 +36,8 @@
+ #include "sandbox/linux/system_headers/linux_time.h"
+ 
++#if !defined(MAP_DROPPABLE)
++#define MAP_DROPPABLE	0x08    // Zero memory under memory pressure.
++#endif
++
+ #if (BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)) && \
+     !defined(__arm__) && !defined(__aarch64__) &&             \
+@@ -239,5 +243,5 @@
+   const uint64_t kAllowedMask = MAP_SHARED | MAP_PRIVATE | MAP_ANONYMOUS |
+                                 MAP_STACK | MAP_NORESERVE | MAP_FIXED |
+-                                MAP_DENYWRITE | MAP_LOCKED |
++                                MAP_DENYWRITE | MAP_LOCKED | MAP_DROPPABLE |
+                                 kArchSpecificAllowedMask;
+   const Arg<int> flags(3);