[Cmake] CMake compilation on dec-alpha OSF1 v 5.0

[Xavier Pierce]

Hi Yogesh,

I noticed you are using the default cxx compiler.  I think this may help.

export CXXFLAGS="-D__USE_STD_IOSTREAM"

Then remove the config.cache and rerun configure to pass this flag to
the compiler.

Let me know how you go.

Cheers,

Xavier