diff --git a/1.patch b/1.patch
new file mode 100644
index 0000000..01af498
--- /dev/null
+++ b/1.patch
@@ -0,0 +1,25 @@
+https://github.com/opensuse-haskell/ghc-rpm-macros/pull/1
+
+From ea3438d89744e6a741c420b1aaaed9004c69af65 Mon Sep 17 00:00:00 2001
+From: "Bernhard M. Wiedemann" <bwiedemann@suse.de>
+Date: Sat, 15 Apr 2023 07:09:01 +0200
+Subject: [PATCH] Compile with only 1 thread
+
+parallel compile causes assignment of random symbol names
+so we build single-threaded, which is slower, but gives reproducible results
+---
+ macros.ghc-suse | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/macros.ghc-suse b/macros.ghc-suse
+index 3fe39a0..7c4a536 100644
+--- a/macros.ghc-suse
++++ b/macros.ghc-suse
+@@ -29,4 +29,6 @@ mkdir -p %{buildroot}/usr/src/debug
+ %with_ghc_prof 1
+ 
+ # %%{?_smp_ncpus_max:--jobs=%%{?_smp_ncpus_max}}
+-%ghc_smp_mflags %{?_smp_mflags}
++# parallel compile causes assignment of random symbol names
++# so we build single-threaded, which is slower, but gives reproducible results
++%ghc_smp_mflags -j1
diff --git a/ghc-rpm-macros.changes b/ghc-rpm-macros.changes
index c3d2b33..3c225fa 100644
--- a/ghc-rpm-macros.changes
+++ b/ghc-rpm-macros.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Mon Jun 26 03:34:18 UTC 2023 - Bernhard Wiedemann <bwiedemann@suse.com>
+
+- Add 1.patch to make ghc builds reproducible (boo#1102408)
+
 -------------------------------------------------------------------
 Sat Mar 18 18:33:27 UTC 2023 - Ondřej Súkup <mimi.vx@gmail.com>
 
diff --git a/ghc-rpm-macros.spec b/ghc-rpm-macros.spec
index 07d5301..42135d6 100644
--- a/ghc-rpm-macros.spec
+++ b/ghc-rpm-macros.spec
@@ -26,6 +26,8 @@ Group:          Development/Libraries/Other
 URL:            https://fedoraproject.org/wiki/Haskell_SIG
 # source gets updated with osc service dr
 Source0:        %{name}-%{version}.tar.xz
+# PATCH-FIX-UPSTREAM https://github.com/opensuse-haskell/ghc-rpm-macros/pull/1
+Patch1:         1.patch
 BuildRequires:  xz
 Requires:       rpm
 Requires:       chrpath
@@ -50,6 +52,7 @@ for example in ghc and haskell-platform.
 
 %prep
 %setup -q
+%patch1 -p1
 
 %build
 echo no build stage needed