Issue #13657: fix build dependencies

We need the gir and plugins to be able to generate the splash image(s).
Add those as dependencies to gimp executable to ensure they are there
when needed.

Fixes: https://gitlab.gnome.org/GNOME/gimp/-/issues/13657

meson.build

@@ -1980,7 +1980,7 @@ if meson.can_run_host_binaries() and have_gobject_introspection
   else
     gimp_real_exe = gimpmain_exe
   endif
-  gimp_exe_depends = [gimp_real_exe]
+  gimp_exe_depends = [gimp_real_exe, libgimp_gir, libgimpui_gir] + plugin_custom_targets
   gimp_run_env.set('GIMP_SELF_IN_BUILD', gimp_real_exe.full_path())
 
   menu_paths=meson.global_build_root() / 'menus:' + meson.global_source_root() / 'menus'

plug-ins/common/meson.build

@@ -186,6 +186,7 @@ if get_option('webkit-unmaintained')
   }
 endif
 
+plugin_custom_targets = []
 foreach plugin : common_plugins_list
   plugin_name = plugin.get('name')
   plugin_sources = [ plugin.get('sources', plugin_name + '.c') ]
@@ -243,7 +244,7 @@ foreach plugin : common_plugins_list
 
   # Ugly trick to copy executables into subfolders so that we can run GIMP from
   # the build directory without installing it.
-  custom_target('test-' + plugin_name,
+  plugin_custom_targets += custom_target('test-' + plugin_name,
                 input: [ plugin_exe ],
                 output: [ plugin_name + '.dummy' ],
                 command: [ python, meson.project_source_root() / 'build/meson/cp-plug-in-subfolder.py',