llvmPackages_git.openmp: apply #197674 (fix cross compile)

this was backported to `llvmPackages_15` in
81ef82a029

pkgs/development/compilers/llvm/git/default.nix

@@ -3,6 +3,7 @@
 , libxml2, python3, fetchFromGitHub, overrideCC, wrapCCWith, wrapBintoolsWith
 , buildLlvmTools # tools, but from the previous stage, for cross
 , targetLlvmLibraries # libraries, but from the next stage, for cross
+, targetLlvm
 # This is the default binutils, but with *this* version of LLD rather
 # than the default LLVM verion's, if LLD is the choice. We use these for
 # the `useLLVM` bootstrapping below.
@@ -296,7 +297,7 @@ let
     };
 
     openmp = callPackage ./openmp {
-      inherit llvm_meta;
+      inherit llvm_meta targetLlvm;
     };
   });
 

pkgs/development/compilers/llvm/git/openmp/default.nix

@@ -6,6 +6,7 @@
 , cmake
 , ninja
 , llvm
+, targetLlvm
 , lit
 , clang-unwrapped
 , perl
@@ -34,7 +35,9 @@ stdenv.mkDerivation rec {
   outputs = [ "out" "dev" ];
 
   nativeBuildInputs = [ cmake ninja perl pkg-config lit ];
-  buildInputs = [ llvm ];
+  buildInputs = [
+    (if stdenv.buildPlatform == stdenv.hostPlatform then llvm else targetLlvm)
+  ];
 
   # Unsup:Pass:XFail:Fail
   # 26:267:16:8

pkgs/top-level/aliases.nix

@@ -1847,6 +1847,7 @@ mapAliases ({
     inherit (stdenvAdapters) overrideCC;
     buildLlvmTools = buildPackages.llvmPackages_git.tools;
     targetLlvmLibraries = targetPackages.llvmPackages_git.libraries or llvmPackages_git.libraries;
+    targetLlvm = targetPackages.llvmPackages_git.llvm or llvmPackages_git.llvm;
   });
 
   # Added 2022-01-28