diff -Nru xrdp-0.9.15/debian/changelog xrdp-0.9.15/debian/changelog
--- xrdp-0.9.15/debian/changelog	2021-03-01 21:27:36.000000000 +0000
+++ xrdp-0.9.15/debian/changelog	2021-09-29 17:29:28.000000000 +0000
@@ -1,3 +1,10 @@
+xrdp (0.9.15-1ubuntu1) impish; urgency=medium
+
+  * debian/patches/known-arch-list.diff: fix build failure on ppc64el
+    and s390x due to unknown arch.
+
+ -- Steve Langasek <steve.langasek@ubuntu.com>  Wed, 29 Sep 2021 10:29:28 -0700
+
 xrdp (0.9.15-1) unstable; urgency=medium
 
   [ Thorsten Glaser ]
diff -Nru xrdp-0.9.15/debian/control xrdp-0.9.15/debian/control
--- xrdp-0.9.15/debian/control	2021-03-01 21:27:36.000000000 +0000
+++ xrdp-0.9.15/debian/control	2021-09-29 17:29:28.000000000 +0000
@@ -1,5 +1,6 @@
 Source: xrdp
-Maintainer: Debian Remote Maintainers <debian-remote@lists.debian.org>
+Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
+XSBC-Original-Maintainer: Debian Remote Maintainers <debian-remote@lists.debian.org>
 Uploaders:
  Dominik George <natureshadow@debian.org>,
  Andreas Tille <tille@debian.org>,
diff -Nru xrdp-0.9.15/debian/patches/known-arch-list.diff xrdp-0.9.15/debian/patches/known-arch-list.diff
--- xrdp-0.9.15/debian/patches/known-arch-list.diff	1970-01-01 00:00:00.000000000 +0000
+++ xrdp-0.9.15/debian/patches/known-arch-list.diff	2021-09-29 17:29:28.000000000 +0000
@@ -0,0 +1,23 @@
+Description: fix build failure on ppc64el and s390x due to unknown arch
+ This package has failed to build on ppc64el and s390x because a previous
+ warning about "unknown arch" has now been promoted to an error.
+ Treat s390x and ppc64el as architectures that do not require alignment -
+ I am not certain this is correct for the code in question, but this was
+ the previous behavior and no one complained, so letting the package build
+ in this configuration without a warning is not a regression.
+Author: Steve Langasek <steve.langasek@ubuntu.com>
+Last-Update: 2021-09-29
+
+Index: xrdp-0.9.15/common/arch.h
+===================================================================
+--- xrdp-0.9.15.orig/common/arch.h
++++ xrdp-0.9.15/common/arch.h
+@@ -85,7 +85,7 @@
+ #elif defined(__x86__) || defined(__x86_64__) || \
+       defined(__AMD64__) || defined(_M_IX86) || defined (_M_AMD64) || \
+       defined(__i386__) || defined(__aarch64__) || \
+-      defined(__riscv)
++      defined(__riscv) || defined(__powerpc64__) || defined(__s390x__)
+ #define NO_NEED_ALIGN
+ #else
+ #warning unknown arch
diff -Nru xrdp-0.9.15/debian/patches/series xrdp-0.9.15/debian/patches/series
--- xrdp-0.9.15/debian/patches/series	2021-03-01 21:26:39.000000000 +0000
+++ xrdp-0.9.15/debian/patches/series	2021-09-29 17:13:22.000000000 +0000
@@ -7,3 +7,4 @@
 pulse-debian.patch
 var-run.diff
 document-certs.diff
+known-arch-list.diff