CMake: Fix qt_find_package to work when CMP00126 is set to NEW

When CMP00126 is set to NEW, set(CACHE) doesn't remove regular
variable bindings with the same name as the cache variable.

This introduced an issue in qt_find_package, which called
find_package(CONFIG QUIET) to try and find a package config file, but
did not clean up the non-cache _FOUND variable which is automatically
set to 0 by CMake if no Config file is found.

Make sure to unset both the regular and cache _FOUND variables if either
the package config file was not found, or if none of the provided
targets found even if the Config file was found.

Also move the _DIR cache variable cleaning into the same code block.

Amends 4c31ce68d5367a6ec4dd3cf2f55e4b226add876d
Amends 34b1c1c23cbddf67f878579bee9d10dcac29d8ca

Fixes: QTBUG-95635
Pick-to: 6.2
Change-Id: I871987217526e0f0a20038a8da52625838e49488
Reviewed-by: Craig Scott <craig.scott@qt.io>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

0 files changed, 0 insertions, 0 deletions