File reproducible-builds.patch of Package ghc-rpm-macros
From fc753c7f752ea77650ca708104acc384f025dd54 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
but give an option to do fast non-deterministic builds
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..61a154a 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 for distribution releases we build single-threaded, which is slower, but gives reproducible results
+# for devel project set ghc_smp_flags in Macros