Use append syntax for classes

The preferred way for bitbake classes is the append syntax because it
does not interact with the += syntax in derived recipes.

classes/cmake_kf5.bbclass

@@ -44,7 +44,7 @@ do_install:prepend() {
 
 BBCLASSEXTEND = "native nativesdk"
 
-FILES:${PN} += " \
+FILES:${PN}:append = " \
     ${datadir}/dbus-1/services/*.service \
     ${datadir}/dbus-1/system-services/*.service \
     ${datadir}/dbus-1/system.d/*.conf \
@@ -57,7 +57,7 @@ FILES:${PN} += " \
 "
 
 # TODO "${datadir}/kdevappwizard/templates/*.tar.bz2" is deprecated, remove when all frameworks are ported away
-FILES:${PN}-dev += " \
+FILES:${PN}-dev:append = " \
     ${datadir}/dbus-1/interfaces/*.xml \
     ${datadir}/kdevappwizard/templates/*.tar.bz2 \
     ${datadir}/kdevfiletemplates/templates/*.tar.bz2 \

classes/kauth.bbclass

@@ -4,10 +4,10 @@
 #
 # SPDX-License-Identifier: MIT
 
-DEPENDS += " \
+DEPENDS:append = " \
     kauth \
     kauth-native \
     polkit-qt-1 \
 "
 
-EXTRA_OECMAKE += " -DKF5_HOST_TOOLING=${STAGING_DIR_NATIVE}/${libdir}/cmake"
+EXTRA_OECMAKE:append = " -DKF5_HOST_TOOLING=${STAGING_DIR_NATIVE}/${libdir}/cmake"

classes/kconfig.bbclass

@@ -4,9 +4,9 @@
 #
 # SPDX-License-Identifier: MIT
 
-DEPENDS += " \
+DEPENDS:append = " \
     kconfig \
     kconfig-native \
 "
 
-EXTRA_OECMAKE += " -DKF5_HOST_TOOLING=${STAGING_DIR_NATIVE}/${libdir}/cmake"
+EXTRA_OECMAKE:append = " -DKF5_HOST_TOOLING=${STAGING_DIR_NATIVE}/${libdir}/cmake"

classes/kdoctools.bbclass

@@ -9,11 +9,11 @@ do_compile:prepend() {
     export XDG_DATA_DIRS=${STAGING_DATADIR}:$XDG_DATA_DIRS
 }
 
-DEPENDS += " \
+DEPENDS:append = " \
     kdoctools \
     kdoctools-native \
     libxslt-native \
     karchive-native \
 "
 
-EXTRA_OECMAKE += " -DKF5_HOST_TOOLING=${STAGING_DIR_NATIVE}/${libdir}/cmake"
+EXTRA_OECMAKE:append = " -DKF5_HOST_TOOLING=${STAGING_DIR_NATIVE}/${libdir}/cmake"

classes/ki18n.bbclass

@@ -7,7 +7,7 @@
 inherit python3native
 inherit gettext
 
-DEPENDS += " \
+DEPENDS:append = " \
     ki18n \
     gettext-native \
 "