--- ./a/mysys/my_cpu.c	2019-07-27 20:18:31.000000000 -0400
+++ ./b/mysys/my_cpu.c	2019-08-05 07:16:48.780583139 -0400
@@ -31,6 +31,8 @@ unsigned my_cpu_relax_multiplier = 200;
 instead of being inlined. Let us fall back to my_timer_cycles(), which
 internally invokes rdtsc. */
 #  include <my_rdtsc.h>
+# elif GCC_VERSION < 4005
+#  include <my_rdtsc.h>
 # else
 #  include <x86intrin.h>
 #  define my_timer_cycles __rdtsc