llvmPackages.openmp: don’t use a target platform LLVM

This was used in 4b07aeae16 to get
what was actually a *host* LLVM in practice, when the `buildHost`
LLVM package set was included in the `callPackage` scope used for
libraries. It should no longer be necessary and is now quite confusing.

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

@@ -108,14 +108,7 @@ let
 in
 makeScopeWithSplicing' {
   inherit otherSplices;
-  extra =
-    spliced0:
-    args
-    // metadata
-    // {
-      inherit buildLlvmPackages;
-      targetLlvm = spliced0.llvm.__spliced._targetTarget or llvm;
-    };
+  extra = _spliced0: args // metadata // { inherit buildLlvmPackages; };
   f =
     self:
     let

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

@@ -9,7 +9,6 @@
   cmake,
   ninja,
   llvm,
-  targetLlvm,
   lit,
   clang-unwrapped,
   perl,
@@ -62,7 +61,7 @@ stdenv.mkDerivation (finalAttrs: {
   ];
 
   buildInputs = [
-    (if stdenv.buildPlatform == stdenv.hostPlatform then llvm else targetLlvm)
+    llvm
   ]
   ++ lib.optionals (ompdSupport && ompdGdbSupport) [
     python3

pkgs/development/rocm-modules/6/llvm/default.nix

@@ -501,7 +501,6 @@ overrideLlvmPackagesRocm (s: {
     with s.final;
     (llvmPackagesRocm.openmp.override {
       llvm = llvm;
-      targetLlvm = llvm;
       clang-unwrapped = clang-unwrapped;
     }).overrideAttrs
       (old: {