Trouble forcing an include with "-include"

[Jeffrey Walton]

I'm trying to test for some C++ features via preprocessor macros. Some
macros (like __GXX_VERSION__) are only triggered by including a C++
standard library file. According to Issue 67195, "cpp and g++ does not
define __GLIBCXX__", I should only need to include c++config.h.

The following is failing to pickup GCC's standard C++ configuration file:

    g++ -include c++config.h -dM -E - < /dev/.null | sort

The command (and variations like "-include c\+\+config.h" and
"-include bits/c++config.h") produces:

    cc1 fatal error: c++config.h: no such file or directory

I also tried with "-std=c++03", but it did not help either.

I'm specifically trying to avoid the physical filesystem by way of
temporary files as input, and temporary files as output. I'm also on a
Debian 7 machine, which provides GCC 4.7.2.

How do I force an include of GCC's standard C++ definition file?

I guess a related question is, why is G++ using cc1, and not cc1plus?

Thanks in advance.