From 5e1b0a10a0fdac966212bdea0b208cc7d8c72e66 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Fri, 26 Nov 2021 17:01:44 +0800
Subject: [PATCH] flake: patch nixpkgs to fix mingw llvm_12 build

---
 flake.nix                    |  2 +-
 llvm-mingw-crosscompile.diff | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 llvm-mingw-crosscompile.diff

diff --git a/flake.nix b/flake.nix
index e63673673..c75bec59a 100644
--- a/flake.nix
+++ b/flake.nix
@@ -10,7 +10,7 @@
       nixpkgs-patched = pkgs-orig.applyPatches {
         name = "nixpkgs";
         src = nixpkgs;
-        patches = [ ./llvm-future-riscv-abi.diff ./llvm-restrict-targets.diff ];
+        patches = [ ./llvm-future-riscv-abi.diff ./llvm-restrict-targets.diff ./llvm-mingw-crosscompile.diff ];
       };
       pkgs = import nixpkgs-patched { system = "x86_64-linux"; };
     in rec {
diff --git a/llvm-mingw-crosscompile.diff b/llvm-mingw-crosscompile.diff
new file mode 100644
index 000000000..09fc6599a
--- /dev/null
+++ b/llvm-mingw-crosscompile.diff
@@ -0,0 +1,35 @@
+diff --git a/pkgs/development/compilers/llvm/12/llvm/default.nix b/pkgs/development/compilers/llvm/12/llvm/default.nix
+index 30a1a7a16df..4f9435d1819 100644
+--- a/pkgs/development/compilers/llvm/12/llvm/default.nix
++++ b/pkgs/development/compilers/llvm/12/llvm/default.nix
+@@ -15,10 +15,11 @@
+ , buildLlvmTools
+ , debugVersion ? false
+ , enableManpages ? false
+-, enableSharedLibraries ? !stdenv.hostPlatform.isStatic
++, enableSharedLibraries ? (!stdenv.hostPlatform.isStatic && !stdenv.targetPlatform.isMinGW)
+ , enablePFM ? !(stdenv.isDarwin
+   || stdenv.isAarch64 # broken for Ampere eMAG 8180 (c2.large.arm on Packet) #56245
+   || stdenv.isAarch32 # broken for the armv7l builder
++  || stdenv.targetPlatform.isMinGW
+ )
+ , enablePolly ? false
+ }:
+@@ -120,7 +121,7 @@ in stdenv.mkDerivation (rec {
+     "-DLLVM_INSTALL_CMAKE_DIR=${placeholder "dev"}/lib/cmake/llvm/"
+     "-DCMAKE_BUILD_TYPE=${if debugVersion then "Debug" else "Release"}"
+     "-DLLVM_INSTALL_UTILS=ON"  # Needed by rustc
+-    "-DLLVM_BUILD_TESTS=ON"
++    "-DLLVM_BUILD_TESTS=${if stdenv.targetPlatform.isMinGW then "OFF" else "ON"}"
+     "-DLLVM_ENABLE_FFI=ON"
+     "-DLLVM_ENABLE_RTTI=ON"
+     "-DLLVM_HOST_TRIPLE=${stdenv.hostPlatform.config}"
+@@ -134,7 +135,7 @@ in stdenv.mkDerivation (rec {
+     "-DSPHINX_OUTPUT_MAN=ON"
+     "-DSPHINX_OUTPUT_HTML=OFF"
+     "-DSPHINX_WARNINGS_AS_ERRORS=OFF"
+-  ] ++ optionals (!isDarwin) [
++  ] ++ optionals (!isDarwin && !stdenv.targetPlatform.isMinGW) [
+     "-DLLVM_BINUTILS_INCDIR=${libbfd.dev}/include"
+   ] ++ optionals isDarwin [
+     "-DLLVM_ENABLE_LIBCXX=ON"