Refuse to compile using buggy Clang versions (14.0.0-14.0.4)

Clang versions 14.0.0 to 14.0.4 (included) miscompile Dr.Jit / Mitsuba.
The default initialization of `DiffArray<...>::m_index` is optimized
away, which then causes crashes when AD reference counting operations
access nonexistent variable indices.

The issue is resolved in 14.0.5. I did not bisect the specific LLVM
commit, though I suspect that the following loop optimization fixes
are involved:

- llvm/llvm-project@b75bf75
- llvm/llvm-project@d350783

Working around the issue looks to be hopeless, to this commit reverts a
previous attempted fix (bfab9ac) and introduces a hard version check.

CMakeLists.txt

@@ -56,6 +56,13 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL GNU)
   target_compile_options(drjit INTERFACE -fno-strict-aliasing)
 endif()
 
+if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT APPLE)
+  if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 14.0.0 AND
+      CMAKE_CXX_COMPILER_VERSION VERSION_LESS 14.0.5)
+    message(FATAL_ERROR "Clang versions 14.0.0 to 14.0.4 miscompile Dr.Jit. Please use either a newer (14.0.5+) or older (e.g., 13.x) version. On Ubuntu, you can use the LLVM project's package server (https://apt.llvm.org) to get the latest version.")
+  endif()
+endif()
+
 if (DRJIT_MASTER_PROJECT)
   if (APPLE)
     set(DRJIT_ORIGIN "@loader_path")

include/drjit/array_base.h

@@ -595,7 +595,7 @@ template <typename Value_, bool IsMask_, typename Derived_> struct ArrayBase {
                       sizeof...(Indices) == Derived::ActualSize, "shuffle(): Invalid size!");
         DRJIT_CHKSCALAR("shuffle_");
         size_t idx = 0; (void) idx;
-        Derived out = zeros<Derived>();
+        Derived out;
         ((out.entry(idx++) = derived().entry(Indices % Derived::Size)), ...);
         return out;
     }