- update to 1.4.19:
* configure: Add missing AC_ARG_VAR for all programs so that they are
documented in --help output, and so that autoconf knows they are "precious"
and preserves them if configure is rerun even when they're specified via an
environment variable.
* Replace uses of obsolete autoconf macros, fixing warnings if configure is
regenerated with a recent release of autoconf.
* Add missing wrappers for some QueryParser FLAG_* constants.
* Fix incorrect formatting in the processed POD documentation due to missing
escaping of `>` in code snippets.
* Make configure PHP5 version check more robust. Previously it would have
incorrectly accepted any (future) PHP version >= 10.0.0.
* configure: We now reject PHP8 since it isn't currently supported
by a released version of SWIG. SWIG 4.1.0 will supports PHP8.
* configure: Check for php-config7.4 as well as earlier 7.x versions
and php-config.
* Fix deprecation warnings with Python >= 3.9.
* Remove more files/dirs on "make clean". Reported by Gaurav Arora.
* Fix build with Ruby 3.0 and clang. Reported by Eduard Panov on macos, where
clang is the default compiler.
* Improve markup in Ruby bindings docs.