Fix harmless compiler warnings.  In the command-line shell, report if the
".system" command returns a non-zero result.
Fix two more harmless compiler warnings.  Make sure the fts3_unicode2.c file
is in sync with mkunicode.tcl.
A couple more harmless compiler warnings eliminated.
When the estimated cost to do a sort overwhelms the estimated cost to do
individual table lookups, make sure that the table lookup costs are still
taken into consideration when selecting the lookup algorithm.
Remove the extraneous debugging printf() from the previous check-in.
Clarify the computation of compatible isOrdered by in the plan solver of
the query planner.
When the estimated sorting cost overwhelms the estimated lookup cost, ensure
that lookup costs are still taken into account when selecting a lookup
algorithm.
Reworking the documentation on integer result codes.  This is a comment
and documentation change only.  There are no changes to code.
The SQLITE_IOERR_BLOCKED extended error code is not longer used, so remove
assert() statements and documentation for that error code.  Also make other
documentation improvements.
Because SQLite internally calculates query plan costs using a logarithmic scale, very large estimated sorting costs can cause all other estimated costs to be rounded down to zero. In these cases break ties between plans with the same total cost by comparing the costs with sorting excluded. This is an alternative fix for the same problem as addressed by [2af630c572].
Fix a buffer overrun in the previous commit.
Improvements to the way the query planner handles sorting costs, so that
very large sorting costs do not overwhelm the loop costs.
Update requirements marks.  No changes to code.
Changes that will perhaps enable SQLite to work better on VxWorks.
Fix harmless compiler warnings.
Updates to evidence marks and requirements.  No changes to code.
Add a few more requirements tests.
Fix for #ifdef issue with GetVersionEx in the Win32 VFS.
Clarify the comment explaining the meaning of the SQLITE_WIN32_GETVERSIONEX
macro in the Windows VFS.
Further clarification and typo fixes for the previous comment change.