Candidate fix for [9f2eb3abac]: Have the whereShortCut() planner ignore indexes with more than four columns.
Restore fix [f15591f802], which was accidentally clobbered by the stat4 merge.
Never leave an open file descriptor pointing into the middle of the
database file if the file descriptor number is 2 or less.
Change the unix VFS so that it refuses to open a database file using
a file descriptor less than 3.
Make the unix VFS defensive against the error of having a database file open
on file descriptors 1 or 2, as an error message might easily be written onto
those file descriptors and thus overwrite and corrupt the database.
Improvements to the robust_open() logic in the unix VFS so that if an attempt
is made to open a repository on file descriptors 0, 1, or 2, and blocking
that file descriptor by opening it on /dev/null fails, then the open will
fail.
Add a test for fts4 unicode61 option remove_diacritics=0.
Add the SQLITE_MINIMUM_FILE_DESCRIPTOR compile-time option, for control over
exactly which low-numbered file descriptors SQLite will use.
If the cost of two whereLoop objects is the same in every way except that
one has fewer expected output rows than the other, then choose the one with
fewer output rows.
Fix comment typos in the where.c module.  No code changes.
Fix comment typo in analyze.c. No changes to code.
Fix compiler warnings in analyze.c.
Add support for Cygwin when handling temporary file names.  Improve error codes and diagnostic messages for temporary file name handling on Windows.  Rename winConvertUtf8Filename to winConvertFromUtf8Filename.  Improve placement and comments for forward function declarations.
Improve the consistency of the diagnostic messages on Windows.
Fix harmless MSVC compiler warning with MEMDEBUG defined.
Avoid commenting out #include statements when building the amalgamation source code file.
Reenable a test accidentally disabled when the stat4 branch was merged.
Enhancements to the Win32 API definition macros.
Fix a problem causing SQLite not to use stat4 or stat3 data to analyze constraints of the form "column = expr COLLATE collation" (those with an explicit COLLATE on the non-column side of the comparison operator).
Revise the amalgamation tool to allow 'duplicate' include files to be retained manually while still preserving the existing line numbers.