[meta-qt5] Antisocial layer behaviour

[Richard Purdie <richard.purdie@linuxfoundation.org>]

I noticed some rebuilds happening when my cache should have been good.
"bitbake xxxx -S printdiff" showed:

Task cmake-native:do_configure couldn't be used from the cache because:
  We need hash f8a8910df42f4330ddaf9e40105baa7d, closest matching task was 93ac4b3cc3e9b5dd0868377cf287ca3d
  basehash changed from 6b93d63cb19070822b91834c3ec58922 to a805733675f04ac021199aa92ed54cb5
  Variable do_configure value changed from '    sed -i 's/^find_package(Qt5Core QUIET)$/#find_package(Qt5Core QUIET)/g' ${S}/Tests/RunCMake/CMakeLists.txt
    sed -i 's/^find_package(Qt5Core REQUIRED)/#find_package(Qt5Core REQUIRED)/g' ${S}/Tests/RunCMake/IncompatibleQt/IncompatibleQt.cmake
    sed -i 's/^  find_package(Qt5Widgets REQUIRED)/#  find_package(Qt5Widgets REQUIRED)/g' ${S}/Tests/QtAutomoc/CMakeLists.txt
    sed -i 's/^find_package(Qt5Core REQUIRED)/#find_package(Qt5Core REQUIRED)/g' ${S}/Tests/Qt4And5Automoc/CMakeLists.txt
    sed -i 's/^  find_package(Qt5Widgets QUIET NO_MODULE)/#  find_package(Qt5Widgets QUIET NO_MODULE)/g' ${S}/Tests/CMakeLists.txt
    sed -i 's/^find_package(Qt5Widgets QUIET)/#find_package(Qt5Widgets QUIET)/g' ${S}/Source/QtDialog/CMakeLists.txt
	./configure --prefix=${prefix}
' to '	./configure --prefix=${prefix}
'

so basically the bbappend in meta-qt5 means that everything using
cmake-native will get rebuilt unless you either include or exclude the
layer everywhere :(

Can we try and find a better way to work around whatever that bbappend
is trying to fix please?

Cheers,

Richard