Roll 4 revisions.
Roll 4 revisions.

Pickup:
  731) -fPIC fix for scons generator
  732) shared library fix for cross-compiling
  734) support for configuration inheritance.

BUG=300013
TEST=try server.

Review URL: http://codereview.chromium.org/343043

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@30513 0039d316-1c4b-4281-b951-d872f2087c98

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