determine which destructor to call for the lookahead upon a syntax
error or upon parser return. This bug has been fixed.
-* Changes in version 2.4.2 (????-??-??):
+* Changes in version 2.4.2 (2010-03-20):
+
+** Some portability problems that resulted in failures and livelocks
+ in the test suite on some versions of at least Solaris, AIX, HP-UX,
+ RHEL4, and Tru64 have been addressed. As a result, fatal Bison
+ errors should no longer cause M4 to report a broken pipe on the
+ affected platforms.
** `%prec IDENTIFIER' requires IDENTIFIER to be defined separately.