by leaving out the choices keyword.

Add an array type to user options

We should always prefer generated files over onces in the source tree
else if the same file also exists in the source tree we get strange
behaviour where we ignore dependencies and the project has to be
built twice to be fully up-to-date.

See: https://bugzilla.gnome.org/show_bug.cgi?id=787677

Closes https://github.com/mesonbuild/meson/issues/2686

One thing that makes cross compiling with meson a pain is the need for
cross files. The problem is not with cross files themselves (they're
actually rather brilliant in that they allow for a much greater deal of
flexibility than autotools hardcoded paths approach) but that each user
needs to reimplement them themselves, when for most people what they
really want is a cross file that could be provided by their distro, all
they really want is the correct toolchain.

This patch is the first stop to making it easier for distros to ship
their own cross files (and for users to put their's somewhere safe so
they don't get `git clean`ed. It allows the cross files (on Linux and
*BSD) to be stored in home and system paths (~/.config/meson/cross,
/usr/share/meson/cross, and /usr/local/share/meson/cross), and to be
loaded by simply by specificying --cross-file.

With this patch meson will check the locations its always checked first,
(is cross file absolute, or is it relative to $PWD), then will check
~/.config/meson/cross, /usr/local/share/meson/cross,
/usr/share/meson/cross, (or $XDG_CONFIG_PATH and $XDG_DATA_DIRS) for the
files, raising an exception if it cannot find the specified cross file.

Fixes #2283

dependencies: Fix parsing of shebangs with spaces

'test cases/frameworks/9 wxwidgets' fails to build with clang on
Fedora because it needs C++11 enabled.

Signed-off-by: Alexis Jeandet <alexis.jeandet@member.fsf.org>

When `ninja -C builddir/ test` is run, ninja will change into the build
dir before starting, but `meson test -C builddir/` does not. This is
important because meson does not use (for good reasons) absolute paths,
which means if a test case needs to be passed as an argument a file name
that is part of the build process, it will be relative builddir. Without
changing into the builddir the path will not exist (or worse, point at
the wrong thing), and test will not behave as intended.

To fix this mtest will change directory before starting tests, and will
change back after all tests have been finished.

Fixes #2710

macos 10.13 fixes