aarch64 port sent by C. Bergstrom

llvm-svn: 225792
diff --git a/openmp/runtime/cmake/HelperFunctions.cmake b/openmp/runtime/cmake/HelperFunctions.cmake
index 88e309b..46f8b26 100644
--- a/openmp/runtime/cmake/HelperFunctions.cmake
+++ b/openmp/runtime/cmake/HelperFunctions.cmake
@@ -67,8 +67,10 @@
         set(${return_arch_string} "L1OM" PARENT_SCOPE)
     elseif(${ARM})
         set(${return_arch_string} "ARM" PARENT_SCOPE)
-	elseif(${PPC64})
-	    set(${return_arch_string} "PPC64" PARENT_SCOPE)
+    elseif(${PPC64})
+        set(${return_arch_string} "PPC64" PARENT_SCOPE)
+    elseif(${AARCH64})                                                                                   
+        set(${return_arch_string} "AARCH64" PARENT_SCOPE)
     else()
         warning_say("set_legal_arch(): Warning: Unknown architecture...")
     endif()