SQLite 3.43.0

What's new in this version:

- Add support for Contentless-Delete FTS5 Indexes. This is a variety of FTS5 full-text search index that omits storing the content that is being indexed while also allowing records to be deleted.
- Added the octet_length(X) SQL function
- Added the sqlite3_stmt_explain() API
- Performance enhancements to JSON processing results in a 2x performance improvement for some kinds of processing on large JSON strings
- New makefile target "verify-source" checks to ensure that there are no unintentional changes in the source tree. (Works for canonical source code only - not for precompiled amalgamation tarballs.)
- Added the SQLITE_USE_SEH compile-time option that enables Structured Exception Handling on Windows while working with the memory-mapped shm file that is part of WAL mode processing. This option is enabled by default when building on Windows using Makefile.msc.
- The VFS for unix now assumes that the nanosleep() system call is available unless compiled with -DHAVE_NANOSLEEP=0

Enhancements to the date and time functions:
- Added new time shift modifiers of the form ±YYYY-MM-DD HH:MM:SS.SSS
- Added the timediff() SQL function

Query planner enhancements:
- Generalize the LEFT JOIN strength reduction optimization so that it works for RIGHT and FULL JOINs as well. Rename it to OUTER JOIN strength reduction
- Enhance the theorem prover in the OUTER JOIN strength reduction optimization so that it returns fewer false-negatives

Enhancements to the decimal extension:
- New function decimal_pow2(N) returns the N-th power of 2 for integer N between -20000 and +20000
- New function decimal_exp(X) works like decimal(X) except that it returns the result in exponential notation - with a "e+NN" at the end
- If X is a floating-point value, then the decimal(X) function now does a full expansion of that value into its exact decimal equivalent