astyle.sh: make it not touch unmodified files

Currently astyle.sh will rewrite files, even if no change are made.
This causes some editors (for example kate) to believe that the file
has been changed even if it is not the case. Letting the timestamp
untouched is not enough. So make 'flip' and 'unify_includes.pl'
operate on copies, and move the copies as the original file if
differences are found.

scripts/astyle.sh

@@ -56,7 +56,11 @@ set -e
 
 astyleit() {
 	$ASTYLE --options="$ASTYLEOPTS" "$1"
-	scripts/unify_includes.pl "$1"
+	modified=$1.unify_includes_modified
+	cp "$1" "$modified"
+	scripts/unify_includes.pl "$modified"
+	diff "$f" "$modified" >/dev/null || mv "$modified" "$1"
+	rm -f "$modified"
 }
 
 for f in "$@"; do
@@ -103,6 +107,10 @@ for f in "$@"; do
 		echo "removed BOM from $f"
 	fi
 
-	flip -ub "$f"
+	modified=$f.flip_modified
+	cp "$f" "$modified"
+	flip -ub "$modified"
+	diff "$f" "$modified" >/dev/null || mv "$modified" "$f"
+	rm -f "$modified"
 	eval "$cmd '$f'"
 done