(validate_else): Don't loop given `#endif /'.

(validate_else): Don't loop given `#endif /'.
Handle multiple	adjacent backslash-newlines correctly.
Accept a new parameter LIMIT to specify end of input;
this prevents confusion when the input contains '\0' characters.

(collect_expansion): Fix off-by-1 error when searching for `*/'
at end of a comment used for traditional token concatenation.

(macarg1): Fix off-by-1 error when skipping past `*/'
at end of comment.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@11330 138bc75d-0d04-0410-961f-82ee72b054a4