Decorate GCC attribute names with underscores to prevent interaction
with user-defined macros.

asio/include/asio/buffers_iterator.hpp

diff --git a/asio/include/asio/buffers_iterator.hpp b/asio/include/asio/buffers_iterator.hpp
index a907471..b5ea984 100644
--- a/asio/include/asio/buffers_iterator.hpp
+++ b/asio/include/asio/buffers_iterator.hpp
@@ -127,7 +127,7 @@
   /// Construct an iterator representing the beginning of the buffers' data.
   static buffers_iterator begin(const BufferSequence& buffers)
 #if BOOST_WORKAROUND(__GNUC__, == 4) && BOOST_WORKAROUND(__GNUC_MINOR__, == 3)
-    __attribute__ ((noinline))
+    __attribute__ ((__noinline__))
 #endif
   {
     buffers_iterator new_iter;
@@ -147,7 +147,7 @@
   /// Construct an iterator representing the end of the buffers' data.
   static buffers_iterator end(const BufferSequence& buffers)
 #if BOOST_WORKAROUND(__GNUC__, == 4) && BOOST_WORKAROUND(__GNUC_MINOR__, == 3)
-    __attribute__ ((noinline))
+    __attribute__ ((__noinline__))
 #endif
   {
     buffers_iterator new_iter;