From b125089f5a8bd6eb1975236a1c2de77a5005cbc9 Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <slyich@gmail.com>
Date: Thu, 12 May 2022 08:22:23 +0100
Subject: [PATCH] alan_2: add -fcommon workaround for gcc-10

Without the change the build against upstream gcc-10 build fails as:

    ld: smScSema.o:/build/source/compiler/smScSema.c:135:
        multiple definition of `charset'; options.o:/build/source/compiler/options.c:16: first defined here

Use -fcommon as a workeround until upstream updates the code.
---
 pkgs/development/compilers/alan/2.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/development/compilers/alan/2.nix b/pkgs/development/compilers/alan/2.nix
index e24cc35a9d7..7329a0115d8 100644
--- a/pkgs/development/compilers/alan/2.nix
+++ b/pkgs/development/compilers/alan/2.nix
@@ -14,6 +14,10 @@ stdenv.mkDerivation rec {
 
   makefile = "Makefile.unix";
 
+  # Add a workarounf for -fno-common tollchains like upstream gcc-10.
+  # alan-3 is already fixed, but the backport is nontrivial.
+  NIX_CFLAGS_COMPILE = "-fcommon";
+
   installPhase = ''
     mkdir -p $out/bin $out/share/alan2
     cp compiler/alan $out/bin/alan2