Support Tru64 in protobuf (with the Symbian solution for the const T& and const T* problem)

This is the patch of the 7041 apply of the r59:
But instead of removing the FormatForFailureMessage which cause some problem with HP C++ on Tru64, we use the solution of the Symbian compiler.

Because, it seem that the HP C++ work in the same way of Symbian....

[choiniere.vincent, 2008-11-14 15:25:13]

This patch should be okai now.

http://codereview.appspot.com/8855/diff/1/15
File src/gtest/internal/gtest-internal.h (right):

http://codereview.appspot.com/8855/diff/1/15#newcode220
Line 220: 

I check for __DECCXX and __osf__ because perhaps this problem does'nt occur with
the HP C++ on linux plateform.

http://codereview.appspot.com/8855/diff/1/15#newcode246
Line 246: }
This part is still there : so the warning problem should not occur.

http://codereview.appspot.com/8855/diff/1/16
File src/gtest/internal/gtest-port.h (right):

http://codereview.appspot.com/8855/diff/1/16#newcode447
Line 447: 
This is the modification for using the Symbian solution.

I check for __DECCXX and __osf__ because perhaps this problem does'nt occur with
the HP C++ on linux plateform.