mcpp V.2.6 released.

MCPP V.2.6 was just released.

MCPP is a portable C/C++ preprocessor, supporting GCC,
Visual C++, etc. Its source is highly configurable and can
generate executables of various specs. It accompanies a
validation suite to check preprocessor's conformance and
quality exhaustively.

The updated points from V.2.5 are as follows.

* Integrated STANDARD mode and PRE_STANDARD mode into one
executable, differentiating the modes by the invocation
options.
* Made stand-alone-build of MCPP independent on any compiler-
systems.
* Revised #pragma once and handling of include directories
list, judging a identity of directory and file by absolute
path, and dereferencing symbolic linked file.
* Added portings to GCC V.4.0, CygWIN 1.5.18, Visual C++
2005.
* Removed support for pre-C90 compilers, MS-DOS compilers.