Toolchain+Ports: Update LLVM to 14.0.1

Besides a version bump, the following changes have been made to our
toolchain infrastructure:
- LLVM/Clang is now built with -march=native if the host compiler
  supports it. An exception to this is CI, as the toolchain cache is
  shared among many different machines there.
- The LLVM tarball is not re-extracted if the hash of the applied
  patches doesn't differ.
- The patches have been split up into atomic chunks.
- Port-specific patches have been integrated into the main patches,
  which will aid in the work towards self-hosting.
- <sysroot>/usr/local/lib is now appended to the linker's search path by
  default.
- --pack-dyn-relocs=relr is appended to the linker command line by
  default, meaning ports take advantage of RELR relocations without any
  patches or additional compiler flags.

The formatting of LLVM port's package.sh has been bothering me, so I
also indented the arguments to the CMake invocation.

Toolchain/Patches/llvm/0007-cmake-Allow-undefined-symbols-on-SerenityOS.patch

@@ -0,0 +1,28 @@
+From ac91fd973bdf23b24645336a470d5dfb31811aa6 Mon Sep 17 00:00:00 2001
+From: Daniel Bertalan <dani@danielbertalan.dev>
+Date: Thu, 14 Apr 2022 10:21:19 +0200
+Subject: [PATCH 7/8] [cmake] Allow undefined symbols on SerenityOS
+
+Allow undefined symbols in LLVM libraries, which is needed because only
+stubs are available for SerenityOS libraries when libc++ and libunwind
+are built.
+---
+ llvm/cmake/modules/HandleLLVMOptions.cmake | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
+index fcaa8f20b..c27209146 100644
+--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
++++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
+@@ -227,7 +227,7 @@ endif()
+ 
+ # Pass -Wl,-z,defs. This makes sure all symbols are defined. Otherwise a DSO
+ # build might work on ELF but fail on MachO/COFF.
+-if(NOT (CMAKE_SYSTEM_NAME MATCHES "Darwin|FreeBSD|OpenBSD|DragonFly|AIX|SunOS|OS390" OR
++if(NOT (CMAKE_SYSTEM_NAME MATCHES "Darwin|FreeBSD|OpenBSD|DragonFly|AIX|SunOS|OS390|SerenityOS" OR
+         WIN32 OR CYGWIN) AND
+    NOT LLVM_USE_SANITIZER)
+   set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,-z,defs")
+-- 
+2.35.3
+