sys-devel/llvm-roc: set default device-libs.

Disable HIP runtime check, it is not needed for Gentoo.

Only the patch is updated, directly move 4.0.0-r1 to -r2.

Closes: https://bugs.gentoo.org/769005
Package-Manager: Portage-3.0.12, Repoman-3.0.1
Signed-off-by: Benda Xu <heroxbd@gentoo.org>

sys-devel/llvm-roc/files/llvm-roc-4.0.0-hip-location.patch

@@ -1,5 +1,7 @@
 replace hardcoded hip finder with Gentoo paths.
 
+It is not necessary to check HIP runtime each time.
+
 Author: Benda Xu <heroxbd@gentoo.org>
 
 Index: llvm-project-rocm-4.0.0/clang/lib/Driver/ToolChains/AMDGPU.cpp
@@ -12,7 +14,7 @@ Index: llvm-project-rocm-4.0.0/clang/lib/Driver/ToolChains/AMDGPU.cpp
  
 -  // Try to find relative to the compiler binary.
 -  const char *InstallDir = D.getInstalledDir();
-+  Candidates.emplace_back(D.SysRoot + "/usr/lib/hip", /*StrictChecking=*/true);
++  Candidates.emplace_back(D.SysRoot + "/usr", /*StrictChecking=*/true);
  
 -  // Check both a normal Unix prefix position of the clang binary, as well as
 -  // the Windows-esque layout the ROCm packages use with the host architecture
@@ -45,3 +47,38 @@ Index: llvm-project-rocm-4.0.0/clang/lib/Driver/ToolChains/AMDGPU.cpp
    return Candidates;
  }
  
+@@ -273,33 +244,7 @@ void RocmInstallationDetector::detectDev
+ }
+ 
+ void RocmInstallationDetector::detectHIPRuntime() {
+-  auto Candidates = getInstallationPathCandidates();
+-  auto &FS = D.getVFS();
+-
+-  for (const auto &Candidate : Candidates) {
+-    InstallPath = Candidate.Path;
+-    if (InstallPath.empty() || !FS.exists(InstallPath))
+-      continue;
+-
+-    BinPath = InstallPath;
+-    llvm::sys::path::append(BinPath, "bin");
+-    IncludePath = InstallPath;
+-    llvm::sys::path::append(IncludePath, "include");
+-    LibPath = InstallPath;
+-    llvm::sys::path::append(LibPath, "lib");
+-
+-    llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> VersionFile =
+-        FS.getBufferForFile(BinPath + "/.hipVersion");
+-    if (!VersionFile && Candidate.StrictChecking)
+-      continue;
+-
+-    if (HIPVersionArg.empty() && VersionFile)
+-      ParseHIPVersionFile((*VersionFile)->getBuffer());
+-
+-    HasHIPRuntime = true;
+-    return;
+-  }
+-  HasHIPRuntime = false;
++  HasHIPRuntime = true;
+ }
+ 
+ void RocmInstallationDetector::print(raw_ostream &OS) const {