package/gobject-introspection: new package

package/gobject-introspection: new package

GObject introspection is a middleware layer between C
libraries (using GObject) and language bindings. The C library
can be scanned at compile time and generate a metadata file,
in addition to the actual native C library. Then at runtime,
language bindings can read this metadata and automatically
provide bindings to call into the C library.

There's an XML format called GIR used by GObject-Introspection.
The purpose of it is to provide a standard structure to access the complete
available API that a library or other unit of code exports. It's
language-agnostic using namespaces to separate core, language, or
library-specific functionality.

Cross-compiling gobject-introspection is not an easy task. The main issue is
that in the process of creating the XML files, gobject-introspection must first
run and scan the binary, which, if the binary is cross-compiled, would not
typically be possible from the host system.

Because of this limitation, we use several wrappers to call instead first out
qemu, which runs the native scanner to create the binaries.

There are seven total patches and four different wrapper files needed to
successfully cross-compile and run this package, many of them are from
open-embedded, but one of them is of my own doing.

1) Revert a previous, incomplete attempt at adding cross-compiling support.

2) Add support for cross-compiling with meson.

3) Disable tests.

4) Add an option to use a binary wrapper; this patch will force giscanner to
   use a wrapper executable to run binaries it's producing, instead of
   attempting to run them from the host.

5) Add an option to use an LDD wrapper, again, useful for cross-compiled
   environments.

6) Add a --lib-dirs-envar option to pass to giscanner. (See patch for details.)

7) Add rpath-links to ccompiler: when passing the PACKAGE_GIR_EXTRA_LIBS_PATH
   to the ccompiler.py script, ccompiler.py needs to add -Wl,-rpath-link to the
   environment for the package to correctly link against the passed on paths.

8) Ignore error return codes from ldd-wrapper because prelink-rtld returns 127
   when it can't find a library, which breaks subprocess.check_output().

Signed-off-by: Adam Duskett <Aduskett@gmail.com>
Tested-by: Yegor Yefremov <yegorslists@googlemail.com>
Tested-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
[yann.morin.1998@free.fr:
  - host-prelink-cross has no Kconfig entry
  - reorder dependencies for arch deps first
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>