The test-meson-builds.sh script correctly detects the source directory and
builds the native builds successfully in a directory outside of the source
tree. However, the paths to the cross-files are not prefixed with the
source directory path, so the cross-builds all fail. Fix this by prepending
the source directory path appropriately.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Luca Boccassi <bluca@debian.org>