Correct version_compare_condition_with_min() for the case where no minimum
version is established by the version constraint. Add a simple test.
Also fix test_feature_check_usage_subprojects by escaping regex
metacharacters.
if |condition| is '<', '<=' or '!=', the minimum version satisfying the
condition is 0, so the minimum version for a feature is never met.
if |condition| is '>=' or '==', the minimum version satisfying the condition
is the version compared with, so the minimum version for a feature must be
less than or equal to that.
if |condition| is '>', the minimum version satisfying the condition is
greater than the version compared with, so the minimum version for a feature
must be less than that
(it's this last condition that makes this function necessary, as in all
other cases we could establish a definite minimum version which we could
compare to see if it's less than or equal to the current version)
We now pass the current subproject to every FeatureNew and
FeatureDeprecated call. This requires a bunch of rework to:
1. Ensure that we have access to the subproject in the list of
arguments when used as a decorator (see _get_callee_args).
2. Pass the subproject to .use() when it's called manually.
3. We also can't do feature checks for new features in
meson_options.txt because that's parsed before we know the
meson_version from project()
Jon Turney
Jussi Pakkanen
Nirbheek Chauhan