c-beginning-of-statement-1: Handle syntactic WS macros properly.

c-beginning-of-statement-1: Handle syntactic WS macros properly.

* lisp/progmodes/cc-engine.el (c-beginning-of-statement-1): The variable
before-sws-pos should record the position of a closing paren/brace/bracket
before moving backwards over a sexp.  When there is a syntactic WS macro
between the starting point and the closing p/b/b, setq before-sws-pos again
after moving backward over the macro.