The Visual Studio Developer Command Prompt always sets the VSINSTALLDIR
environment variable. If not, we probably have a broken environment and
won't get very far anyway.
Currently, we only consider the build depends of the Executable being
run when serializing custom targets. However, this is not always
sufficient, for example if the executable loads modules at runtime or if
the executable is actually a python script that loads a built module.
For these cases, we need to set PATH on Windows correctly or the custom
target will fail to run at build time complaining about missing DLLs.
Currently, run_target does not get namespaced for each subproject,
unlike executable and others. This means that two subprojects sharing
the same run_target name cause meson to crash.
Fix this by moving the subproject namespacing logic from the BuildTarget
class to the Target class.
/WHOLEARCHIVE must go to AdditionalOptions, not AdditionalDependencies
and we must add a project reference to trick msbuild/visual studio into
building a target that is built from only libraries linked in via
/WHOLEARCHIVE.
This allows a CustomTarget to be indexed, and the resulting indexed
value (a CustomTargetIndex type), to be used as a source in other
targets. This will confer a dependency on the original target, but only
inserts the source file returning by index the original target's
outputs. This can allow a CustomTarget that creates both a header and a
code file to have it's outputs split, for example.
Fixes#1470
This also adds a "# noqa: F401" comment on an unused "import lzma",
which we are using it in a try/except block that is being used to
check if the lzma module is importable; of course it is unused.
v2: This turned out to be a little tricky.
mesonbuild/modules/__init__.py had the "unused" import:
from ..interpreterbase import permittedKwargs, noKwargs
However, that meant that the various modules could do things like:
from . import noKwargs # "." is "mesonbuild.modules"
Which breaks when you remove __init__.py's "unused" import. I
could have tagged that import with "# noqa: F401", but instead I
chose to have each of the module import directly from
"..interpreterbase" instead of ".".
Custom target include dirs must be overridable by target-specific
include dirs otherwise in case of header name collisions, the user has
no way to override this behaviour.