diff -Nru ghc-8.8.4/debian/changelog ghc-8.8.4/debian/changelog
--- ghc-8.8.4/debian/changelog	2020-12-23 22:15:42.000000000 +0000
+++ ghc-8.8.4/debian/changelog	2021-09-30 18:21:04.000000000 +0000
@@ -1,3 +1,18 @@
+ghc (8.8.4-2+rpi2) bookworm-staging; urgency=medium
+
+  * Add upstream patch to fix build with new autoconf.
+
+ -- Peter Michael Green <plugwash@raspbian.org>  Thu, 30 Sep 2021 18:21:04 +0000
+
+ghc (8.8.4-2+rpi1) bullseye-staging; urgency=medium
+
+  [changes brought forward from 7.6.3-21+rpi1 by Peter Michael Green <plugwash@raspbian.org> at Sun, 19 Apr 2015 14:00:16 +0000]
+  * Change compiler defaults for armv6
+  [changed introduced in 7.10.3-2+rpi1 by Peter Michael Green]
+  * Add call to dh_autoreconf_clean
+
+ -- Raspbian forward porter <root@raspbian.org>  Sun, 27 Dec 2020 19:30:12 +0000
+
 ghc (8.8.4-2) unstable; urgency=medium
 
   [ Ilias Tsitsimpis ]
diff -Nru ghc-8.8.4/debian/patches/ARM-VFPv3D16 ghc-8.8.4/debian/patches/ARM-VFPv3D16
--- ghc-8.8.4/debian/patches/ARM-VFPv3D16	2020-12-23 22:15:42.000000000 +0000
+++ ghc-8.8.4/debian/patches/ARM-VFPv3D16	2020-12-27 19:30:12.000000000 +0000
@@ -13,9 +13,10 @@
 @@ -454,7 +454,7 @@ AC_DEFUN([GET_ARM_ISA],
                  )],
                  [changequote(, )dnl
-                  ARM_ISA=ARMv7
+-                 ARM_ISA=ARMv7
++                 ARM_ISA=ARMv6
 -                 ARM_ISA_EXT="[VFPv3,NEON]"
-+                 ARM_ISA_EXT="[VFPv3D16,NEON]"
++                 ARM_ISA_EXT="[VFPv2]"
                   changequote([, ])dnl
                  ])
          ])
diff -Nru ghc-8.8.4/debian/patches/autoconf-2.71.patch ghc-8.8.4/debian/patches/autoconf-2.71.patch
--- ghc-8.8.4/debian/patches/autoconf-2.71.patch	1970-01-01 00:00:00.000000000 +0000
+++ ghc-8.8.4/debian/patches/autoconf-2.71.patch	2021-09-30 18:21:04.000000000 +0000
@@ -0,0 +1,27 @@
+From ad2ef3a13f1eb000eab8e3d64592373b91a52806 Mon Sep 17 00:00:00 2001
+From: Moritz Angermann <moritz.angermann@gmail.com>
+Date: Wed, 17 Feb 2021 21:13:07 +0800
+Subject: [PATCH] [configure] Fix _AC_PROG_CC_99
+
+_AC_PROG_CC_99 isn't available anymore in recent autoconf versions.
+This broke on aarch64-darwin.
+---
+ aclocal.m4 | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/aclocal.m4 b/aclocal.m4
+index 259db63dbff..99f77d910cf 100644
+--- a/aclocal.m4
++++ b/aclocal.m4
+@@ -659,7 +659,7 @@ AC_DEFUN([FP_SET_CFLAGS_C99],
+     CPPFLAGS="$$3"
+     unset ac_cv_prog_cc_c99
+     dnl perform detection
+-    _AC_PROG_CC_C99
++    AC_PROG_CC_C99
+     fp_cc_c99="$ac_cv_prog_cc_c99"
+     case "x$ac_cv_prog_cc_c99" in
+       x)   ;; # noop
+-- 
+GitLab
+
diff -Nru ghc-8.8.4/debian/patches/series ghc-8.8.4/debian/patches/series
--- ghc-8.8.4/debian/patches/series	2020-12-23 22:15:42.000000000 +0000
+++ ghc-8.8.4/debian/patches/series	2021-09-30 18:21:04.000000000 +0000
@@ -14,3 +14,4 @@
 11f8eef5a9625c77f78a829406c446b615ed6168.patch
 haddock-remove-googleapis-fonts
 fix-big-endian-ffi
+autoconf-2.71.patch
diff -Nru ghc-8.8.4/debian/rules ghc-8.8.4/debian/rules
--- ghc-8.8.4/debian/rules	2020-12-23 22:15:42.000000000 +0000
+++ ghc-8.8.4/debian/rules	2020-12-27 19:30:12.000000000 +0000
@@ -290,6 +290,8 @@
 	rm -f utils/ghc-pwd/dist-boot/Main.o
 	rm -f utils/ghc-pwd/dist-boot/ghc-pwd
 
+	dh_autoreconf_clean
+
 	rm -f libraries/haskeline/a.out
 	rm -rf utils/ghctags/dist-install