build-llvm: Update to the final 16.0.0 release

Notable changes for mingw users are:
- Support demangling C++ symbols on i386 in LLVM backtraces
- Don't report fatal errors when the output pipe is closed on Windows
- Ignore file access times on Windows when comparing whether files are
  equivalent

build-llvm.sh

@@ -16,7 +16,7 @@
 
 set -e
 
-: ${LLVM_VERSION:=llvmorg-16.0.0-rc1}
+: ${LLVM_VERSION:=llvmorg-16.0.0}
 ASSERTS=OFF
 unset HOST
 BUILDDIR="build"