package/qt6/qt6tools: build without clang support

Fixes:
If external clang is available on the host system, the buildsystem tries
to use it. The result will be unpredictable. We can't use the version of
clang that is shipped with buildroot either, because it is too old. See:
https://code.qt.io/cgit/qt/qttools.git/tree/.cmake.conf?h=6.8.1. So we
disable clang support in qt6tools for now.

Signed-off-by: Roy Kollen Svendsen <roykollensvendsen@gmail.com>
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>
(cherry picked from commit ac7f65d83e57843951df843be65bbf2e79531ec7)
Signed-off-by: Thomas Perale <thomas.perale@mind.be>

package/qt6/qt6tools/qt6tools.mk

@@ -36,6 +36,10 @@ QT6TOOLS_CONF_OPTS = \
 	-DQT_BUILD_EXAMPLES=OFF \
 	-DQT_BUILD_TESTS=OFF
 
+# Disable clang support in qt6tools for now, as version 17 is needed:
+# https://code.qt.io/cgit/qt/qttools.git/tree/.cmake.conf?h=6.8.1
+QT6TOOLS_CONF_OPTS += -DFEATURE_clang=OFF
+
 QT6TOOLS_DEPENDENCIES = \
 	qt6base \
 	host-qt6tools
@@ -50,6 +54,10 @@ HOST_QT6TOOLS_CONF_OPTS = \
 	-DQT_BUILD_EXAMPLES=OFF \
 	-DQT_BUILD_TESTS=OFF
 
+# Disable clang support in qt6tools for now, as version 17 is needed:
+# https://code.qt.io/cgit/qt/qttools.git/tree/.cmake.conf?h=6.8.1
+HOST_QT6TOOLS_CONF_OPTS += -DFEATURE_clang=OFF
+
 HOST_QT6TOOLS_DEPENDENCIES = host-qt6base
 
 ifeq ($(BR2_PACKAGE_HOST_QT6TOOLS_LINGUIST_TOOLS),y)