fix: kf6-ki18n — force -include stdlib.h for strtold visibility

GCC <cstdlib> does 'using ::strtold;' which requires strtold declared in
global namespace. relibc declares it correctly in stdlib.h, but Qt's
include chain (qchar.h → qglobal.h → ... → cstdlib) pulls in cstdlib
before stdlib.h is fully processed. Adding -include stdlib.h ensures
the C stdlib declarations are in scope before any C++ header.

local/recipes/kde/kf6-ki18n/recipe.toml

@@ -40,6 +40,8 @@ cmake "${COOKBOOK_SOURCE}" \
     -DCMAKE_INSTALL_PREFIX=/usr \
     -DCMAKE_BUILD_TYPE=Release \
     -DCMAKE_PREFIX_PATH="${COOKBOOK_SYSROOT}" \
+    -DCMAKE_C_FLAGS="-include stdlib.h" \
+    -DCMAKE_CXX_FLAGS="-include stdlib.h" \
     -DCMAKE_C_STANDARD_LIBRARIES="-liconv" \
     -DCMAKE_CXX_STANDARD_LIBRARIES="-liconv" \
     -DCMAKE_SHARED_LINKER_FLAGS="-liconv" \