Index: ext/raindrops/extconf.rb
--- ext/raindrops/extconf.rb.orig
+++ ext/raindrops/extconf.rb
@@ -134,7 +134,7 @@ SRC
   if try_link(src)
     $defs.push(format("-DHAVE_GCC_ATOMIC_BUILTINS"))
     true
-  else
+  elsif false
     # some compilers still target 386 by default, but we need at least 486
     # to run atomic builtins.
     prev_cflags = $CFLAGS
