cygwin32.h (NO_IMPLICIT_EXTERN_C): Don't assume anything about system headers.

cygwin32.h (NO_IMPLICIT_EXTERN_C): Don't assume anything about system headers.

        * i386/cygwin32.h (NO_IMPLICIT_EXTERN_C): Don't assume anything
        about system headers.
        (LIB_SPEC): Add -ladvapi32 -lshell32 to be consistent with mingw32
        and also to resolve symbols in prefix.c.
        * i386/xm-cygwin32.h (HAVE_BCOPY): Define. This avoids a conflict
        between gansidecl.h and newlib's _ansi.h when building libgcc2.a,
        when the definitions in auto-config.h is not visible.
        (HAVE_BZERO): Likewise.
        (HAVE_BCMP): Likewise.
        (HAVE_RINDEX): Likewise.
        (HAVE_INDEX): Likewise.

From-SVN: r17177