Users may wish to make use of these files for their own purposes.
For example, the -pot and -update-po pseudo targets could be reused in
an alias_target(), and at least one person wanted to reuse the built .mo
files as custom_target input.
Fixes#6227
This simplifies things for us, as we don't have to have threading
imported for no other reason, and we can remove the
`an_unpicklable_object` from the Interpreter and mesonlib, since there
was only one user of this.
This caught a couple of cases of us doing:
```python
for i in range(len(x)):
v = x[i]
```
which are places to use enumerate instead.
It also caught a couple of cases of:
```python
assert len(x) == len(y)
for i in range(len(x)):
xv = x[i]
yv = y[i]
```
Which should instead be using zip()
```python
for xv, yv in zip(x, y):
...
```
We have a lot of these. Some of them are harmless, if unidiomatic, such
as `if (condition)`, others are potentially dangerous `assert(...)`, as
`assert(condtion)` works as expected, but `assert(condition, message)`
will result in an assertion that never triggers, as what you're actually
asserting is `bool(tuple[2])`, which will always be true.
This didn't actually catch what it's supposed to, which is cases of:
```python
for x in dict.keys():
y = dict[x]
```
But it did catch one unnecessary use of keys(), and one case where we
were doing something in an inefficient way. I've rewritten:
```python
if name.value in [x.value for x in self.kwargs.keys() if isinstance(x, IdNode)]:
```
as
``python
if any((isinstance(x, IdNode) and name.value == x.value) for x in self.kwargs):
```
Which avoids doing two iterations, one to build the list, and a
second to do a search for name.value in said list, which does a single
short circuiting walk, as any returns as soon as one check returns True.
Currently, EnvironmentVariablesObject is a strange
holder-that's-not-a-holder. This has implicaitons for things that expect
to get an EnvironmentVariables object, as we can't automatically
unholder it, and instead have to to manually do so. Now we can
automatically unholder it, which makes everything much nicer.
Because currently you can write something like:
```python
KwargInfo('capture', bool)
```
Which proclaims "this must be bool", but the default is then not valid.
This is useful information for solving the OS bootstrapping problem.
Give it some visibility.
Also, I don't want to forget where I found any of these. :D
ref. #2335
The sysconfig paths are, by default, correct for every OS -- they are
supposed to follow the scheme that python knows about per default.
For some reason, this overrode the scheme to posix_prefix, which is the
default for posix OSes like linux and macOS, but wrong on Windows.
Simply deleting this entirely makes everything that used to work, still
work, and a couple new things start working.