c++/6579: Infinite loop with statement expressions in member initialization

[Joe Buck]

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6579

PR's 6579 and 7679 appear to be duplicates.  The infinite loop appears 
to be in spew.c,
in yylex(), and is possibly related to error recovery.