Fixes #4786: Move r29732 to v1.8 branch (BUILD: support new automake)

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r29732 [[BR]]
Changes to VT/OTF:
Fixed warnings about the need of the 'subdir-objects' option when using Automake v1.14.
Due to a bug in Automake (see http://debbugs.gnu.org/cgi/bugreport.cgi?bug=13928) the 'subdir-objects' option cannot be enabled.
To get around this problem external sources files are sym linked in the current build directory (as done in ompi/mpi/c/profile) to lead Automake to believe that all source files are in the same directory.