We don't want any fiddling with -march, our flags via %optflags are always right

--- configure.py
+++ configure.py
@@ -1081,7 +1081,7 @@
                                      options.cpu, options.debug_build),
 
         'lib_opt': cc.library_opt_flags(options),
-        'mach_opt': cc.mach_opts(options.arch, options.cpu),
+        'mach_opt': '',
         'check_opt': '' if options.no_optimizations else cc.check_opt_flags,
         'lang_flags': cc.lang_flags + options.extra_flags,
         'warn_flags': warning_flags(cc.warning_flags,