MR !10753 breaks macOS build for plugin unit test as its linker doesn't
supports `--wrap` option, which is used in in order to mock the function
`isc_file_exits()`.
To work around the problem, a mocked `isc_file_exits()` is implemented
inside the plugin test as a static function before inlining the file
using it, which effectively links to this version rather than the isclib
one.
Update existing ns_plugin_expandpath() unit test to cover the logic
appending the plugin extension if missing.
Because ns_plugin_expandpath() now relies on isc_file_exists() API, a
mocked version has been added in tests/ns/plugin_test.c and relies on the
linker --wrap mechanism.
Meson is a modern build system that has seen a rise in adoption and some
version of it is available in almost every platform supported.
Compared to automake, meson has the following advantages:
* Meson provides a significant boost to the build and configuration time
by better exploiting parallelism.
* Meson is subjectively considered to be better in readability.
These merits alone justify experimenting with meson as a way of
improving development time and ergonomics. However, there are some
compromises to ensure the transition goes relatively smooth:
* The system tests currently rely on various files within the source
directory. Changing this requirement is a non-trivial task that can't
be currently justified. Currently the last compiled build directory
writes into the source tree which is in turn used by pytest.
* The minimum version supported has been fixed at 0.61. Increasing this
value will require choosing a baseline of distributions that can
package with meson. On the contrary, there will likely be an attempt
to decrease this value to ensure almost universal support for building
BIND 9 with meson.
