build-llvm: Bump to LLVM 23.1.0 RC 2

This version includes a fix for linking directly against an ARM64X
DLL.

build-llvm.sh

@@ -17,7 +17,7 @@
 set -e
 
 : ${LLVM_REPOSITORY:=https://github.com/llvm/llvm-project.git}
-: ${LLVM_VERSION:=llvmorg-23.1.0-rc1}
+: ${LLVM_VERSION:=llvmorg-23.1.0-rc2}
 ASSERTS=OFF
 unset HOST
 BUILDDIR="build"