meta: Bump llvm to 20.

Author: sleepy-monax

meta/scripts/setup-ubuntu.sh

@@ -6,4 +6,4 @@ export DEBIAN_FRONTEND=noninteractive
 
 apt-get update -y --no-install-recommends
 apt-get install -y --no-install-recommends ccache build-essential git ninja-build libsdl2-dev nasm gcc-multilib qemu-system-x86 mtools liburing-dev
-bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" llvm 19 all
+bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" llvm 20 all