Support 'mailfrom' option

tools/git/gitmail

@@ -168,6 +168,12 @@ my @archivemail = get_config("archivemail",undef);
 #
 my $replyto = get_config("replyto",undef);
 
+#
+# If set, set the 'From' header in the mail - useful when being called
+# from outside to set make the sender look right
+#
+my $mailfrom = get_config("mailfrom",undef);
+
 #
 # If set to true, detach and run in background - the push doesn't return until
 # the hook finishes, so doing this means the pusher doesn't have to wait for
@@ -1121,6 +1127,11 @@ sub send_mail($$$@) {
                open(MAIL, "| $SENDMAIL -odb -oem -t");
         }
 
+        # If requested, set the From header
+        if (defined($mailfrom)) {
+            print MAIL "From: $mailfrom\n";
+        }
+
         print MAIL "To: " . join(", ",@$mailto) . "\n";
         print MAIL "Subject: $subject\n";
         print MAIL "Message-Id: $messageid\n";