extconf.rb in raindrops-0.4.1

- old
+ new

@@ -1,8 +1,7 @@
 require 'mkmf'
 
-# FIXME: test for GCC __sync_XXX builtins here, somehow...
 have_func('mmap', 'sys/mman.h') or abort 'mmap() not found'
 have_func('munmap', 'sys/mman.h') or abort 'munmap() not found'
 
 have_func("rb_struct_alloc_noinit")
 have_func('rb_thread_blocking_region')
@@ -16,9 +15,16 @@
         return 0;
 }
 SRC
 
   if try_run(src)
+    # some systems target GCC for i386 and don't get the atomic builtins
+    # when building shared objects
+    arch = `#{CONFIG['CC']} -dumpmachine`.split(/-/)[0]
+    if arch == "i386" && $CFLAGS !~ /\b-march=/
+      $CFLAGS += " -march=i486 "
+    end
+
     $defs.push(format("-DHAVE_GCC_ATOMIC_BUILTINS"))
     true
   else
     false
   end