This is more correct, and forces the target(s) to be rebuilt if the
PDB files are missing. Increases the minimum required Ninja to 1.7,
which is available in Ubuntu 16.04 under backports.
We can't do the same for import libraries, because it is impossible
for us to know at configure time whether or not an import library will
be generated for a given DLL.
Currently it's just like if all builtin/base/compiler options are
yielding. This patch makes possible to have non-yielding builtin
options. The value in is overriden in this order:
- Value from parent project
- Value from subproject's default_options if set
- Value from subproject() default_options if set
- Value from command line if set
The documentation of "order-only" dependencies is limited and their
various purposes are especially not clear. See issue #6391 for a recent
example, search the internet for many more. So mention the particular
purpose here while making the documentation barely longer.
This allows Meson native-file [properties] to be used.
This avoids the need to call meson from a script file or have a
long command line invocation of `meson setup`
The method meson.get_native_property('prop', 'fallback') is added.
The native file can contain properties like
```
[properties]
myprop1 = 'foo'
mydir2 = 'lib/custom'
```
Then from within `meson.build`
```meson
x1 = meson.get_native_property('myprop1')
thedir = meson.get_native_property('mydir2', 'libs')
```
fallback values are optional
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