libide: fix various -Wmissing-declarations

1 job for master in 14 minutes and 27 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #48770
flatpak

00:14:27

 
Name Stage Failure
failed
flatpak Test
Found git repository at /builds/GNOME/gnome-builder
Configuring ide-debug.h using configuration
Program python3 found: YES (/usr/bin/python3)
Native dependency webkit2gtk-4.0 found: YES 2.20.2

src/libide/meson.build:219:2: ERROR: Unknown variable "libide_args".

A full log can be found at /builds/GNOME/gnome-builder/_build/meson-logs/meson-log.txt
ERROR: Job failed: exit code 1