[EDG eccp 3.10] error on std::mblen() in src/wcodecvt.cpp

$ nice make BUILDTYPE=11s BUILDDIR=/build/sebor/stdcxx-4.2.1-eccp-3.10.1-11s CONFIG=eccp.config
...
eccp -c -I/home/sebor/stdcxx-4.2.1/include/ansi -D_RWSTDDEBUG    -I/home/sebor/stdcxx-4.2.1/include -I/build/sebor/stdcxx-4.2.1-eccp-3.10.1-11s/include  -A -x --template_directory=/build/sebor/stdcxx-4.2.1-eccp-3.10.1-11s/lib -g   --display_error_number --remarks --diag_suppress 193,236,340,401,261,479,487,678,679,815    /home/sebor/stdcxx-4.2.1/src/wcodecvt.cpp
"/home/sebor/stdcxx-4.2.1/src/wcodecvt.cpp", line 90: error #159: declaration
          is incompatible with previous "std::mblen" (declared at line 110 of
          "/home/sebor/stdcxx-4.2.1/include/ansi/_cstdlib.h")
  mblen (const char*, _RWSTD_SIZE_T) _LIBC_THROWS();
  ^

"/home/sebor/stdcxx-4.2.1/src/wcodecvt.cpp", line 90: error #734: function
          "mblen(const char *, unsigned int) C" conflicts with
          using-declaration of function
          "std::mblen(const char *, std::size_t) C"
  mblen (const char*, _RWSTD_SIZE_T) _LIBC_THROWS();
  ^

2 errors detected in the compilation of "/home/sebor/stdcxx-4.2.1/src/wcodecvt.cpp".
make[2]: *** [wcodecvt.o] Error 2
make[2]: Leaving directory `/build/sebor/stdcxx-4.2.1-eccp-3.10.1-11s/lib'
make[1]: *** [lib] Error 2
make[1]: Leaving directory `/build/sebor/stdcxx-4.2.1-eccp-3.10.1-11s'
make: *** [libstd] Error 2