pidgin/pidgin

Update Meson to newer standards

2021-10-18, Elliott Sales de Andrade
1653402dd94e
Update Meson to newer standards

* Remove checks for old Meson
We require 0.56.0 now.
* Remove deprecated Meson call
* Update calls to `pkgconfig.generate`
The library to wrap should be passed as first positional argument, and we can
pass actual dependencies as the runtime requirements. We can't pass things that
might be subprojects as dependencies, which may be a Meson bug, so pass those
ones as strings.

Testing Done:
Re-configured and looked at the pkgconfig files.

Reviewed at https://reviews.imfreedom.org/r/1064/
#define PIDGIN_ICON 104
#define PIDGIN_TRAY_AVAILABLE_4BIT 105
#define PIDGIN_TRAY_AWAY_4BIT 106
#define PIDGIN_TRAY_BUSY_4BIT 107
#define PIDGIN_TRAY_XA_4BIT 108
#define PIDGIN_TRAY_OFFLINE_4BIT 109
#define PIDGIN_TRAY_CONNECTING_4BIT 110
#define PIDGIN_TRAY_PENDING_4BIT 111
#define PIDGIN_TRAY_INVISIBLE_4BIT 112