Change non-target indentation in Makefile to spaces to fix make error

Makefile

@@ -8,26 +8,26 @@ CC=clang
 OS=$(shell uname)
 
 ifeq ($(OS), Darwin)
-	LLVM_CONFIG=llvm-config
+    LLVM_CONFIG=llvm-config
 
-	LDFLAGS:=$(LDFLAGS) -liconv
-	CFLAGS:=$(CFLAGS) $(shell $(LLVM_CONFIG) --cxxflags --ldflags)
-	LDFLAGS:=$(LDFLAGS) -lLLVM-C
+    LDFLAGS:=$(LDFLAGS) -liconv
+    CFLAGS:=$(CFLAGS) $(shell $(LLVM_CONFIG) --cxxflags --ldflags)
+    LDFLAGS:=$(LDFLAGS) -lLLVM-C
 endif
 ifeq ($(OS), Linux)
-	LLVM_CONFIG=llvm-config-11
-	ifneq ($(shell which llvm-config-11 2>/dev/null),)
-	    LLVM_CONFIG=llvm-config-11
-	else
-	        ifneq ($(shell llvm-config --version | grep '^11\.'),)
-	                LLVM_CONFIG=llvm-config
-	        else
-	                $(error "Requirement: llvm-config must be version 11")
-	        endif
-	endif
-
-	CFLAGS:=$(CFLAGS) $(shell $(LLVM_CONFIG) --cxxflags --ldflags)
-	LDFLAGS:=$(LDFLAGS) $(shell $(LLVM_CONFIG) --libs core native --system-libs)
+    LLVM_CONFIG=llvm-config-11
+    ifneq ($(shell which llvm-config-11 2>/dev/null),)
+        LLVM_CONFIG=llvm-config-11
+    else
+            ifneq ($(shell llvm-config --version | grep '^11\.'),)
+                    LLVM_CONFIG=llvm-config
+            else
+                    $(error "Requirement: llvm-config must be version 11")
+            endif
+    endif
+
+    CFLAGS:=$(CFLAGS) $(shell $(LLVM_CONFIG) --cxxflags --ldflags)
+    LDFLAGS:=$(LDFLAGS) $(shell $(LLVM_CONFIG) --libs core native --system-libs)
 endif
 
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