[Sun C++] warnings on std::strstream::rdbuf hiding std::ios::rdbuf

Compiling the header strstream causes Sun C++ to emit warnings like those below:

CC -c -D_RWSTDDEBUG -mt -D_RWSTD_USE_CONFIG -I/amd/devco/sebor/dev/stdlib/include -I/build/sebor/sunpro-5.8.j8/include -library=%none -g +w /amd/devco/sebor/dev/stdlib/src/strstream.cpp
"/amd/devco/sebor/dev/stdlib/include/strstream", line 188: Warning: std::istrstream::rdbuf hides the function std::ios::rdbuf(std::streambuf *).
"/amd/devco/sebor/dev/stdlib/include/strstream", line 226: Warning: std::ostrstream::rdbuf hides the function std::ios::rdbuf(std::streambuf *).
"/amd/devco/sebor/dev/stdlib/include/strstream", line 266: Warning: std::strstream::rdbuf hides the function std::ios::rdbuf(std::streambuf *).
3 Warning(s) detected.