clover: Fix build with llvm-12.

Fix build error after LLVM commit c495dfe0268b ("[clang][cli] NFC:
Decrease the scope of ParseLangArgs parameters").

../src/gallium/frontends/clover/llvm/invocation.cpp: In function ‘std::unique_ptr<clang::CompilerInstance> {anonymous}::create_compiler_instance(const clover::device&, const string&, const std::vector<std::__cxx11::basic_string<char> >&, std::string&)’:
../src/gallium/frontends/clover/llvm/invocation.cpp:252:55: error: cannot convert ‘clang::PreprocessorOptions’ to ‘std::vector<std::__cxx11::basic_string<char> >&’
  252 |                                 c->getPreprocessorOpts(),
      |                                 ~~~~~~~~~~~~~~~~~~~~~~^~
      |                                                       |
      |                                                       clang::PreprocessorOptions

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/4114
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8543>

src/gallium/frontends/clover/llvm/compat.hpp

@@ -38,14 +38,14 @@
 
 #include <llvm/Config/llvm-config.h>
 
+#include <llvm/ADT/Triple.h>
+#include <llvm/Analysis/TargetLibraryInfo.h>
+#include <llvm/IR/LegacyPassManager.h>
 #include <llvm/IR/LLVMContext.h>
 #include <llvm/Linker/Linker.h>
+#include <llvm/Target/TargetMachine.h>
 #include <llvm/Transforms/IPO.h>
 #include <llvm/Transforms/Utils/Cloning.h>
-#include <llvm/Target/TargetMachine.h>
-
-#include <llvm/IR/LegacyPassManager.h>
-#include <llvm/Analysis/TargetLibraryInfo.h>
 
 #include <clang/Basic/TargetInfo.h>
 #include <clang/Frontend/CompilerInstance.h>
@@ -88,6 +88,20 @@ namespace clover {
                cinv, copts.data(), copts.data() + copts.size(), diag);
 #endif
          }
+
+         static inline void
+         compiler_set_lang_defaults(std::unique_ptr<clang::CompilerInstance> &c,
+                                    clang::InputKind ik, const ::llvm::Triple& triple,
+                                    clang::LangStandard::Kind d)
+         {
+            c->getInvocation().setLangDefaults(c->getLangOpts(), ik, triple,
+#if LLVM_VERSION_MAJOR >= 12
+                                               c->getPreprocessorOpts().Includes,
+#else
+                                               c->getPreprocessorOpts(),
+#endif
+                                               d);
+         }
       }
    }
 }

src/gallium/frontends/clover/llvm/invocation.cpp

@@ -247,9 +247,8 @@ namespace {
       // http://www.llvm.org/bugs/show_bug.cgi?id=19735
       c->getDiagnosticOpts().ShowCarets = false;
 
-      c->getInvocation().setLangDefaults(c->getLangOpts(),
-                                compat::ik_opencl, ::llvm::Triple(target.triple),
-                                c->getPreprocessorOpts(),
+      compat::compiler_set_lang_defaults(c, compat::ik_opencl,
+                                ::llvm::Triple(target.triple),
                                 get_language_version(opts, device_clc_version));
 
       c->createDiagnostics(new clang::TextDiagnosticPrinter(