From cc2738c71ad454dba35cb8c33c4fce2481e344e7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phan=20Kochen?= <git@stephank.nl>
Date: Tue, 14 Mar 2023 22:38:19 +0100
Subject: [PATCH] swift: reduce closure size of swift-lib

---
 pkgs/development/compilers/swift/compiler/default.nix | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/compilers/swift/compiler/default.nix b/pkgs/development/compilers/swift/compiler/default.nix
index 5f37c3ec841b..0c0083c334aa 100644
--- a/pkgs/development/compilers/swift/compiler/default.nix
+++ b/pkgs/development/compilers/swift/compiler/default.nix
@@ -619,7 +619,12 @@ in stdenv.mkDerivation {
     # Swift has a separate resource root from Clang, but locates the Clang
     # resource root via subdir or symlink. Provide a default here, but we also
     # patch Swift to prefer NIX_CC if set.
-    ln -s ${clang}/resource-root $lib/lib/swift/clang
+    #
+    # NOTE: We don't symlink directly here, because that'd add a run-time dep
+    # on the full Clang compiler to every Swift executable. The copy here is
+    # just copying the 3 symlinks inside to smaller closures.
+    mkdir $lib/lib/swift/clang
+    cp -P ${clang}/resource-root/* $lib/lib/swift/clang/
 
     ${lib.optionalString stdenv.isDarwin ''
     # Install required library for ObjC interop.