-mcpu=native -> -mtune=native

configure

@@ -7069,6 +7069,46 @@ else $as_nop
   :
 fi
 
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether C compiler accepts -mtune=native" >&5
+printf %s "checking whether C compiler accepts -mtune=native... " >&6; }
+if test ${ax_cv_check_cflags___mtune_native+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+
+  ax_check_save_flags=$CFLAGS
+  CFLAGS="$CFLAGS  -mtune=native"
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <time.h>
+int
+main (void)
+{
+time_t x; int fodder = 0; if (fodder > -1000 && time(&x)) return (int) x
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ax_cv_check_cflags___mtune_native=yes
+else $as_nop
+  ax_cv_check_cflags___mtune_native=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+  CFLAGS=$ax_check_save_flags
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ax_cv_check_cflags___mtune_native" >&5
+printf "%s\n" "$ax_cv_check_cflags___mtune_native" >&6; }
+if test "x$ax_cv_check_cflags___mtune_native" = xyes
+then :
+  CFLAGS="$CFLAGS -mtune=native"
+else $as_nop
+  :
+fi
+
 
 fi
 

configure.ac

@@ -202,6 +202,7 @@ AC_ARG_ENABLE(opt,
     AX_CHECK_COMPILE_FLAG([-ftree-slp-vectorize], [CFLAGS="$CFLAGS -ftree-slp-vectorize"])
     AX_CHECK_COMPILE_FLAG([-fomit-frame-pointer], [CFLAGS="$CFLAGS -fomit-frame-pointer"])
     AX_CHECK_COMPILE_FLAG([-march=native], [CFLAGS="$CFLAGS -march=native"])
+    AX_CHECK_COMPILE_FLAG([-mtune=native], [CFLAGS="$CFLAGS -mtune=native"])
   ])
 ])