The old binary/url is no longer available, and the layout of the
sourceforge archvie seems to have changed to include a new
old_versions/ directory where the previous binary is
relocated.

https://sourceforge.net/projects/winflexbison/files/old_versions/

While we could use that, it seem better to invest the effort to
adapt the scipt afterwards to use the github archives instead

https://github.com/lexxmark/winflexbison/releases

So for now bump the version to get the subproject building
till we switch to github releases.

If automatic bash prompt override is enabled via the 'GST_BUILD_DISABLE_PS1_OVERRIDE',
We should set the bash prompt to have a visual indicator of the "gst-uninstalled" environment
even if bash script file does not exist.

On Fedora 64-bit, libdir is 'lib64'. Just add it unconditionally
everywhere because we have no reliable way of detecting which distros
or OSes will use that.

People should not run `meson` on gst-build inside the uninstalled env.
It will cause problems because meson will detect the already-built
libraries and pkg-config files.

This is not obvious to people, and they often make this mistake.

This option was added so we could remove the sysroot path from the env
when cross-build is used over NFS. Though, the implementation wasn't complete
and went unnoticed.

This moves the sysroot path removal into the helper that prepends env so
that no more env get forgotten. This notably fixes the PATH environment.

The doc is not currently built in cross-compilation, but we still had
some meson code that eneded up being called and failed.

Niels De Graef authored May 31, 2019 and Niels De Graef committed May 31, 2019

This means we can use some newer features and get rid of some
boilerplate code using the G_DECLARE_* macros.

As discussed on IRC, 2.44 is old enough by now to start depending on it.

When using hotdoc, one can build the documentation for a single
subproject (eg. the GL plugins). In that case, hotdoc will look
up links in devhelp indexes available in standard locations.

To make sure this case works, we thus need to add the path to
our devhelp index to XDG_DATA_DIRS. This also means when running
devhelp from inside the environment, the devhelp books produced
by hotdoc will now show up.

The refactored code was only adding paths to plugins in projects
that build hotdoc, which is not the case of gst-python for example

Fixes gst-docs#36

Basically meson detects that we pass file paths to run_command to regenerate the build.ninja file when those change

Otherwise we might be missing some subprojects update

This is useful to check that a build didn't result in changes in the
code/generated files

This will be used to check that the plugins documentation cache file is
properly commited, and that necessary workaround for particular case
are adopted.

To build the documentation, we are maintaining a 'standardise' `plugins`
variable accross all modules to list all plugins and generate
documentation for them.

This is also used to get the right plugin path when inspecting plugins
for the documentation.

As the data from meson is no longer relative path, it is not longer
possible to move gst-build around and run gst-uninstalled.py. This broke
cross-compilation usage, where you build on a host and run over NFS on
target. This adds an option to tell the script to strip off the host path
to the sysroot.

Fixes #30.

Preparing for building API documentation with hotdoc

Also add a note about installation

We will add more data soon.

These subproject dirs are only ignored if they are directories if you
use a trailing slash.

Missed adjustment from commit d3029ec0.

Tested on Windows.

Try even harder to not hit the maximum length limit for env var values
on Windows. Reduces the size by ~1000 characters on my machine.

Helps us avoid breaching the maximum length limit for env var values
on Windows.

This fixes #21

When relying on a system-wide libnice, we end up not building
the nice elements, which means we can't use them, and by extension
webrtcbin, in the uninstalled environment.

This also introduces a way to avoid checking the version of
a given subproject, and makes use of it for libnice and pygobject,
which only passed the version check by chance, as its current
major version is 3.