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-6.8.3-gperf3.2.patch

@@ -0,0 +1,26 @@
+Patch status: fixed in >=chromium-137.0.7126.0
+
+A old workaround for a gperf-3.1 issue[1] breaks building with the
+now fixed gperf-3.2, backport the conditional check[2] which should
+work with either.
+
+[1] https://savannah.gnu.org/bugs/index.php?53029
+[2] https://crrev.com/f8f21fb4aa01f75acbb12abf5ea8c263c6817141
+--- a/src/3rdparty/chromium/third_party/blink/renderer/build/scripts/gperf.py
++++ b/src/3rdparty/chromium/third_party/blink/renderer/build/scripts/gperf.py
+@@ -36,8 +36,11 @@
+         gperf_output = re.sub(r'\bregister ', '', gperf_output)
+         # -Wimplicit-fallthrough needs an explicit fallthrough statement,
+-        # so replace gperf's /*FALLTHROUGH*/ comment with the statement.
+-        # https://savannah.gnu.org/bugs/index.php?53029
+-        gperf_output = gperf_output.replace('/*FALLTHROUGH*/',
+-                                            '  [[fallthrough]];')
++        # so replace gperf 3.1's /*FALLTHROUGH*/ comment with the statement.
++        # https://savannah.gnu.org/bugs/index.php?53029 (fixed in 3.2)
++        if re.search(
++                r'/\* C\+\+ code produced by gperf version 3\.[01](\.\d+)? \*/',
++                gperf_output):
++            gperf_output = gperf_output.replace('/*FALLTHROUGH*/',
++                                                '  [[fallthrough]];')
+         # -Wpointer-to-int-cast warns about casting pointers to smaller ints
+         # Replace {(int)(long)&(foo), bar} with