It appears qemu-kvm does *not* require -machine accel=tcg option.
That problem disappeared after upgrading seabios(!)  However leave the
test for qemu -help option, since that's useful to determine if qemu
is completely broken or not.
 ])
     fi
 
-    # qemu since 0.15 requires the -machine accel=tcg option, otherwise
-    # it won't start up.  QEMU DEVELOPERS, PLEASE ADD CAPABILITIES TESTING.
-    AC_MSG_CHECKING([if this qemu has the -machine accel=tcg option])
-    if $QEMU -help 2>&1 | grep -sq -- '-machine.*accel.*tcg'; then
-        qemu_machine_accel_tcg="-machine accel=tcg"
-        AC_MSG_RESULT([$qemu_machine_accel_tcg])
-    else
-        AC_MSG_RESULT([no])
-    fi
-
     AC_MSG_CHECKING([for virtio-serial support in $QEMU])
-    if $QEMU $qemu_machine_accel_tcg -nographic -device \? 2>&1 | grep -sq virtio-serial; then
+    if $QEMU -nographic -device \? 2>&1 | grep -sq virtio-serial; then
         AC_MSG_RESULT([yes])
     else
         AC_MSG_RESULT([no])