Merge from trunk.

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  r61172 | chris_kohlhoff | 2010-04-10 16:54:34 +1000 (Sat, 10 Apr 2010) | 2 lines
  
  Try using asm-based fenced block for pathscale.
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[SVN r61198]

libs/asio

@@ -1 +1 @@
-Subproject commit d5c95589ffcff918ee797dbb6994a2d2089a47ac
+Subproject commit 2fde542c542d201b7a34cc51927439b5110eaf2c