fix for the #include_next, v4 (final)

fix for the #include_next, v4 (final)

    This version looks rigth. Comparing to the original
    algorithm:

    1) Loop breaking. We remember a start point after wich
    we can try next path. Do not search include stack after
    this.

    2) But compare next file patch with the start point.
    Skip if it the same. Remove "./" before comparing.

    PS: a problems with compaling a coreutils-8.24.51-8802e
    remain. There are errors messages like:
    src/chgrp
        src/chown-core.c:42: multiple definition of `make_timespec'
        src/chgrp.c:42: first defined here
    A problem is in the lib/config.h
        #define _GL_INLINE_ extern inline // gcc
        #define _GL_INLINE_ inline        // tcc

    A long description from the lib/config.h
    * suppress extern inline with HP-UX cc, as it appears to be broken
    * suppress extern inline with Sun C in standards-conformance mode
    * suppress extern inline on configurations that mistakenly use
      'static inline' to implement functions or macros in standard
      C headers like <ctype.h>.

    GCC and Clang are excluded from this list. Why not tcc?