Update prebuilt Clang to r416183b from Android.

https://android.googlesource.com/platform/prebuilts/clang/host/
linux-x86/+/06a71ddac05c22edb2d10b590e1769b3f8619bef

clang 12.0.5 (based on r416183b) from build 7284624.

Change-Id: I277a316abcf47307562d8b748b84870f31a72866
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/linux-x64/clang/lib64/cmake/llvm/LLVMConfigExtensions.cmake b/linux-x64/clang/lib64/cmake/llvm/LLVMConfigExtensions.cmake
new file mode 100644
index 0000000..7bc4079
--- /dev/null
+++ b/linux-x64/clang/lib64/cmake/llvm/LLVMConfigExtensions.cmake
@@ -0,0 +1 @@
+set(LLVM_STATIC_EXTENSIONS Polly)
\ No newline at end of file