cmake: only update config_headers.h if contents changed.
authorGustavo Sverzut Barbieri <barbieri@profusion.mobi>
Mon, 23 Jan 2017 16:33:30 +0000 (14:33 -0200)
committerMarcel Hollerbach <marcel-hollerbach@t-online.de>
Mon, 23 Jan 2017 17:23:41 +0000 (18:23 +0100)
commite36a444c541d5dd47857321dd55bae5e1bdf51c9
tree73c44ead537857e9c2805cf32eae46e1281448b6
parentfe7a21170c5aa568425556c1b33d240bd13bc17c
cmake: only update config_headers.h if contents changed.

Generate to a temporary location and avoid touching the original file
if it's unchanged. This way we play nicer with build system that
regenerate objects based on file timestamps.
cmake/helpers/CommonHeaderChecks.cmake