Udate Darwin's LTO specs to match what's in gcc/gcc.c

gcc/
	* config/darwin.h (LINK_COMMAND_SPEC_A): Sync LTO options with
	the sequence used in gcc/gcc.c.

From-SVN: r263770

gcc/ChangeLog

 2018-08-22  Iain Sandoe  <iain@sandoe.co.uk>
 
+	* config/darwin.h (LINK_COMMAND_SPEC_A): Sync LTO options with
+	the sequence used in gcc/gcc.c.
+
+2018-08-22  Iain Sandoe  <iain@sandoe.co.uk>
+
 	PR other/704
 	* gcc-ar.c (main): Don’t try to invoke the plug-in if we’re not
 	building it.

gcc/config/darwin.h

@@ -175,7 +175,7 @@ extern GTY(()) int darwin_ms_struct;
     %(linker)" \
     LINK_PLUGIN_SPEC \
     "%{flto*:%<fcompare-debug*} \
-    %{flto*} \
+     %{flto} %{fno-lto} %{flto=*} \
     %l " LINK_COMPRESS_DEBUG_SPEC \
    "%X %{s} %{t} %{Z} %{u*} \
     %{e*} %{r} \