lib.sh: support any command on find_exec()

right now, we assume "find", but it adds any number of
arguments next to that.

change it instead to support any command, where the
assumption is that it would generate a list of files
and directories.

Signed-off-by: Leah Rowe <leah@libreboot.org>

mk

@@ -279,7 +279,7 @@ check_project_hashes()
 	[ ! -f "$XBMK_CACHE/hash/$project$tree" ] || \
 	    read -r old_pjhash < "$XBMK_CACHE/hash/$project$tree"
 
-	fx_ "x_ sha512sum" "$datadir" "$configdir/$tree" "$mdir" \
+	fx_ "x_ sha512sum" find "$datadir" "$configdir/$tree" "$mdir" \
 	    -type f -not -path "*/.git*/*" | awk '{print $1}' > \
 	    "$xbmktmp/project.hash" || err "!h $project $tree"
 
@@ -371,7 +371,7 @@ check_defconfig()
 elfcheck()
 {
 	# TODO: *STILL* very hacky check. do it properly (based on build.list)
-	( fx_ "exit 1" "$dest_dir" -type f ) || return 1; :
+	( fx_ "exit 1" find "$dest_dir" -type f ) || return 1; :
 }
 
 handle_makefile()