Changes to required llvm version 13 as both 12 and 11 don't work correctly on macOS Apple Silicon

Makefile

@@ -8,11 +8,21 @@ CC=clang
 OS=$(shell uname)
 
 ifeq ($(OS), Darwin)
+    ARCH=$(shell uname -m)
     LLVM_CONFIG=llvm-config
-    ifneq ($(shell llvm-config --version | grep '^11\.'),)
+
+    # LLVM Version Setting  
+    LLVM_VERSION_PATTERN="^11\."
+    LLVM_VERSION="11"
+    ifeq ($(ARCH), arm64)
+	LLVM_VERSION="13"
+        LLVM_VERSION_PATTERN="^13"
+    endif 
+
+    ifneq ($(shell llvm-config --version | grep $(LLVM_VERSION_PATTERN)),)
         LLVM_CONFIG=llvm-config
     else
-        $(error "Requirement: llvm-config must be version 11")
+        $(error "Requirement: llvm-config must be version $(LLVM_VERSION)")
     endif
 
     LDFLAGS:=$(LDFLAGS) -liconv