This both moves the env reading to configuration time, which is useful,
and also simplifies the implementation of the boost dependency. The
simplification comes from being able to delete basically duplicated code
since the values will be in the Properties if they exist at all.
This removes the check for "mingw" for platform.system(). The only case I know
where "mingw" is return is if using a msys Python under a msys2 mingw environment.
This combination is not really supported by meson and will result in weird errors,
so remove the check.
The second change is checking sys.platform for cygwin instead of platform.system().
The former is document to return "cygwin", while the latter is not and just
returns uname().
While under Cygwin it uname() always starts with "cygwin" it's not hardcoded in MSYS2
and starts with the environment name. Using sys.platform is safer here.
Fixes#7552
Machine files already supports `+` operator as an implementation detail,
since it's using eval(). Now make it an officially supported feature and
add a way to define constants that are used while evaluating an entry
value.
The comment for this code is correct, but the code itself isn't. The way
it's implemented in a cross compile we don't look at PKG_CONFIG_PATH at
all.
Fixes: #7062
PR #6363 made it so our interpretation of env vars no longer clashed
with Autoconf's: if both Meson and Autoconf would read and env var, both
would do the same things with the value they read.
However, there were still cases that autoconf would read an env var when
meson wouldn't:
- Autoconf would use `CC` in cross builds too
- Autoconf would use `CC_FOR_BUILD` in native builds too.
There's no reason Meson can't also do this--if native cross files
overwrite rather than replace env vars, cross files can also overwrite
rather than replace env vars.
Because variables like `CC` are so ubiquitous, and because ignoring them
in cross builds just makes those builds liable to break (and things more
complicated in general), we bring Meson's behavior in line with
Autoconf's.
The rust code is ugly, because rust is annoying. It doesn't invoke a
linker directly (unless that linker is link.exe or lld-link.exe),
instead it invokes the C compiler (gcc or clang usually) to do it's
linking. Meson doesn't have good abstractions for this, though we
probably should because some of the D compilers do the same thing.
Either that or we should just call the c compiler directly, like vala
does.
This changes the public interface for meson, which we don't do unless we
absolutely have to. In this case I think we need to do it. A fair number
of projects have already been using 'ld' in their cross/native files to
get the ld binary and call it directly in custom_targets or generators,
and we broke that. While we could hit this problem again names like
`c_ld` and `cpp_ld` are far less likely to cause collisions than `ld`.
Additionally this gives a way to set the linker on a per-compiler basis,
which is probably in itself very useful.
Fixes#6442
A compiler or other tool with an empty string as name does not make
sense as it anyway can not be used and causes a failure later in
parse_entry.
Fix#5451
Meson itself *almost* only cares about the build and host platforms. The
exception is it takes a `target_machine` in the cross file and exposes
it to the user; but it doesn't do anything else with it. It's therefore
overkill to put target in `PerMachine` and `MachineChoice`. Instead, we
make a `PerThreeMachine` only for the machine infos.
Additionally fix a few other things that were bugging me in the process:
- Get rid of `MachineInfos` class. Since `envconfig.py` was created, it
has no methods that couldn't just got on `PerMachine`
- Make `default_missing` and `miss_defaulting` work functionally. That
means we can just locally bind rather than bind as class vars the
"unfrozen" configuration. This helps prevent bugs where one forgets
to freeze a configuration.
