- fix broken build 4.16.6

- fix possinle int overflow

- fix meson build

- minor code cleaning

- fix regress tests for arm macos

- fix win build

- fix update script for 4.15--4.16

- fix meson build

- fix tag number - tag was not equal to PostreSQL extension version 4…

….14 x 4.15

- the result of months_between is more accurate (to Oracle) when input is timestamp. Originally
  months_between was only for date datatype, and timestamp was casted to date. Now, months_between
  is calculated correctly for timestamp too.

- fix messy work with shortlife memory context in dbms_sql

- fix trigger functions oracle.replace_empty_strings and oracle.repla…

…ce_null_strings for correct work with type char(n)