Enable the AVR backend of LLVM (#49006)

Co-authored-by: Sukera <Seelengrab@users.noreply.github.com>

Author: Seelengrab

deps/llvm.mk

@@ -64,7 +64,7 @@ endif
 LLVM_LIB_FILE := libLLVMCodeGen.a
 
 # Figure out which targets to build
-LLVM_TARGETS := host;NVPTX;AMDGPU;WebAssembly;BPF
+LLVM_TARGETS := host;NVPTX;AMDGPU;WebAssembly;BPF;AVR
 LLVM_EXPERIMENTAL_TARGETS :=
 
 LLVM_CFLAGS :=