rest_proxy_call_sync: bail out if no payload

See merge request !30

It's possible for `_rest_proxy_send_message` to return `NULL`,
which would mean the `payload` here would be `NULL`. If so,
we're not going to be able to do anything, so we should just
bail out.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

goa-daemon is crashing on suspend/resume with a traceback that
points here: it calls rest_proxy_call_sync, that calls
_rest_proxy_send_message, assumes it gets a `payload` back,
and calls `finish_call` with it. However, it's not actually
guaranteed that `_rest_proxy_send_message` will return a payload
(a `GBytes`). There are three ways it can return `NULL` instead:
if it's passed a wrong proxy or message, or - when built against
libsoup3 - if there is an error sending the message (it passes
through the return value of `soup_session_send_and_read`, and
that's documented to be `NULL` on error).

If `payload` comes back `NULL`, let's just return `FALSE`, like
we do if there's a problem with the call or message.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

specify gi-docgen as a native dependency

See merge request !33

Allow to use rest-extras from a single header

See merge request !31

rest-extras: Enhance the annotation coverage

Closes #4

See merge request !32

Change license of rest/rest.h to LGPL 2.1 from LGPL 3 (Fix #21)

Closes #21

See merge request !34

Fix the declaration of the RestOAuth2Error quark function

See merge request !29

This file was introduced in 6d65d886
with a license different than the whole project (LGPL 3 vs LGPL 2.1).
Currently, that makes the impossible to redistribute librest under
LGPL 2.1 because of the license of this file.

this allows for cross-compilation.

other gnome projects already specifying gi-docgen as native dependency:
- [gtk](https://gitlab.gnome.org/GNOME/gtk/-/blob/8cf3a95d8cd5c79d941b6430f00647caa9b52eb0/docs/reference/meson.build#L4)
- [libadwaita](https://gitlab.gnome.org/GNOME/libadwaita/-/blob/fc27700ea2463c9670cd2fb264697d52cba68b89/doc/meson.build#L27)
- [libhandy](https://gitlab.gnome.org/GNOME/libhandy/-/blob/691fa96e17172a7c1605c59005ea8021cdf3d056/doc/meson.build#L18)

The missing `void` breaks the strict prototypes warning.

In C, a function with no arguments and a function with `void` as an
argument are fundamentally different; the former can be called with any
argument, while the latter can only be called with no arguments.

Since rest_oauth2_error_quark() is defined with `void` by the
G_DEFINE_QUARK macro, its declaration should be made to match.

Several consumer-oriented fixes

See merge request !27

This allows it to be used in the GObject introspection

Fixes some missing symbols that are supported by Vala but not by the
GObject introspection yet.

The pkg-config is only declaring the rest-1.0 directory so we always need to use
rest/rest-foo.h and not rest-foo.h

Also make sure to include all the headers.

The parameters are not optional as they are always accessed. They can be NULL
when the iter is finished, actually always set it so that we are sure to
always have an initialized variable

Allows bindings to use the single header

Release 0.9.1

See merge request !26

OAuth1 is discouraged to be used nowadays. Only flickr is the only
service we used in the past which needed oauth1. They probably
won't update their API to OAuth2 and therefore it was dropped
in GOA. Following this example, dropping OAuth1 support too for librest.

meson: Add soupapiversion to pkg-config file

Closes #12

See merge request !25

Fixes #12

meson: build with soup3 by default

Closes #11

See merge request !24

Fixes #11

Allow convenient use of librest as a subproject

See merge request !23

Meson allows projects to specify the dependency object when used as
subprojects; this avoids having to know the variable name to import into
the superproject.

See: https://mesonbuild.com/Reference-manual_builtin_meson.html#mesonoverride_dependency

This fixes problems with bindings if they want to free resources

ci: Use upstream check-abi

See merge request !21

OAuth2Proxy.fetch_access_token: Provide client secret

See merge request !20

build: Fix typo

See merge request !19