+/*
+ * How to build the first jmpenv.
+ *
+ * top_env needs to be non-zero. It points to an area
+ * in which longjmp() stuff is stored, as C callstack
+ * info there at least is thread specific this has to
+ * be per-thread. Otherwise a 'die' in a thread gives
+ * that thread the C stack of last thread to do an eval {}!
+ */
+
+#define JMPENV_BOOTSTRAP \
+ STMT_START { \
+ Zero(&PL_start_env, 1, JMPENV); \
+ PL_start_env.je_ret = -1; \
+ PL_start_env.je_mustcatch = TRUE; \
+ PL_top_env = &PL_start_env; \
+ } STMT_END
+
+/*
+ * PERL_FLEXIBLE_EXCEPTIONS
+ *
+ * All the flexible exceptions code has been removed.
+ * See the following threads for details:
+ *
+ * http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2004-07/msg00378.html
+ *
+ * Joshua's original patches (which weren't applied) and discussion:
+ *
+ * http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01396.html
+ * http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01489.html
+ * http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01491.html
+ * http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01608.html
+ * http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02144.html
+ * http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02998.html
+ *
+ * Chip's reworked patch and discussion:
+ *
+ * http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1999-03/msg00520.html
+ *
+ * The flaw in these patches (which went unnoticed at the time) was
+ * that they moved some code that could potentially die() out of the
+ * region protected by the setjmp()s. This caused exceptions within
+ * END blocks and such to not be handled by the correct setjmp().
+ *
+ * The original patches that introduces flexible exceptions were:
+ *
+ * http://public.activestate.com/cgi-bin/perlbrowse?patch=3386
+ * http://public.activestate.com/cgi-bin/perlbrowse?patch=5162
+ */
+