Merge branch 'ch/am-header'

* ch/am-header:
  git-am: force egrep to use correct characters set
  git-am: fixed patch_format detection according to RFC2822

git-am.sh

@@ -205,7 +205,7 @@ check_patch_format () {
 			# and see if it looks like that they all begin with the
 			# header field names...
 			sed -n -e '/^$/q' -e '/^[ 	]/d' -e p "$1" |
-			egrep -v '^[A-Za-z]+(-[A-Za-z]+)*:' >/dev/null ||
+			LC_ALL=C egrep -v '^[!-9;-~]+:' >/dev/null ||
 			patch_format=mbox
 		fi
 	} < "$1" || clean_abort