s3backer: Use fuse4x as a default FUSE provider

Closes Homebrew/homebrew#6079.
Closes Homebrew/homebrew#7712.

Signed-off-by: Charlie Sharpsteen <source@sharpsteen.net>

Formula/s3-backer.rb

@@ -6,16 +6,18 @@ class S3Backer < Formula
   sha1 'badc003ffb0830a3fa59c9f39f13ad94729cbcf1'
 
   depends_on 'pkg-config' => :build
+  depends_on 'fuse4x'
 
   def install
+    inreplace "configure", "-lfuse", "-lfuse4x"
     system "./configure", "--prefix=#{prefix}"
     system "make install"
   end
 
   def caveats
     <<-EOS.undent
-    This depends on the MacFUSE installation from http://code.google.com/p/macfuse/
-    MacFUSE must be installed prior to installing this formula.
+      Make sure to follow the directions given by `brew info fuse4x-kext`
+      before trying to use a FUSE-based filesystem.
     EOS
   end
 end