Avoid setting x86-specific getarch flags on non-x86

cmake/system.cmake

@@ -71,9 +71,11 @@ if (X86_64)
 endif ()
 
 # On x86 no AVX support is available
+if (X86 OR X86_64)
 if ((DEFINED BINARY AND BINARY EQUAL 32) OR ("$CMAKE_SIZEOF_VOID_P}" EQUAL "4"))
   set(GETARCH_FLAGS "${GETARCH_FLAGS} -DNO_AVX -DNO_AVX2 -DNO_AVX512")
 endif ()
+endif ()
 
 if (INTERFACE64)
   message(STATUS "Using 64-bit integers.")