gnome: Restore dependency of g-ir-scanner on gobject-introspection

g-ir-scanner is a pair of Python script + pymod, and the latter must be
available at any time the script is executed. The changes in the below
commit removed the ordering guarantee, breaking GStreamer introspection
building on Windows when using the monorepo.

This reverts commit ab57be7.

Fixes #14908

Author: amyspark

mesonbuild/modules/gnome.py

@@ -254,6 +254,7 @@ class GnomeModule(ExtensionModule):
 
     def __init__(self, interpreter: 'Interpreter') -> None:
         super().__init__(interpreter)
+        self.gir_dep: T.Optional[Dependency] = None
         self.giscanner: T.Optional[ToolType] = None
         self.gicompiler: T.Optional[ToolType] = None
         self.install_glib_compile_schemas = False
@@ -787,18 +788,20 @@ def postconf_hook(self, b: build.Build) -> None:
         if self.devenv is not None:
             b.devenv.append(self.devenv)
 
-    def _get_gi(self, state: 'ModuleState') -> T.Tuple[ToolType, ToolType]:
-        if not self.giscanner:
-            self.giscanner = self._find_tool(state, 'g-ir-scanner', for_machine=MachineChoice.BUILD)
-            self.gicompiler = self._find_tool(state, 'g-ir-compiler', for_machine=MachineChoice.HOST)
-        return self.giscanner, self.gicompiler
+    def _get_gir_dep(self, state: 'ModuleState') -> T.Tuple[Dependency, T.Union[Executable, 'ExternalProgram', 'OverrideProgram'],
+                                                            T.Union[Executable, 'ExternalProgram', 'OverrideProgram']]:
+        if not self.gir_dep:
+            self.gir_dep = state.dependency('gobject-introspection-1.0')
+            self.giscanner = self._find_tool(state, 'g-ir-scanner')
+            self.gicompiler = self._find_tool(state, 'g-ir-compiler')
+        return self.gir_dep, self.giscanner, self.gicompiler
 
     def _giscanner_version_compare(self, state: 'ModuleState', cmp: str) -> bool:
         # Support for --version was introduced in g-i 1.58, but Ubuntu
         # Bionic shipped 1.56.1. As all our version checks are greater
         # than 1.58, we can just return False if get_version fails.
         try:
-            giscanner, _ = self._get_gi(state)
+            giscanner, _, _ = self._get_gir_dep(state)
             return mesonlib.version_compare(giscanner.get_version(), cmp)
         except MesonException:
             return False
@@ -994,8 +997,6 @@ def _make_gir_target(
         run_env.set('CFLAGS', [quote_arg(x) for x in env_flags], ' ')
         run_env.merge(kwargs['env'])
 
-        giscanner, _ = self._get_gi(state)
-
         # response file supported?
         rspable = self._giscanner_version_compare(state, '>= 1.85.0')
 
@@ -1149,7 +1150,7 @@ def generate_gir(self, state: 'ModuleState', args: T.Tuple[T.List[T.Union[Execut
         if len(girtargets) > 1 and any(isinstance(el, Executable) for el in girtargets):
             raise MesonException('generate_gir only accepts a single argument when one of the arguments is an executable')
 
-        giscanner, gicompiler = self._get_gi(state)
+        gir_dep, giscanner, gicompiler = self._get_gir_dep(state)
 
         ns = kwargs['namespace']
         nsversion = kwargs['nsversion']
@@ -1160,13 +1161,14 @@ def generate_gir(self, state: 'ModuleState', args: T.Tuple[T.List[T.Union[Execut
         builddir = os.path.join(state.environment.get_build_dir(), state.subdir)
 
         depends: T.List[T.Union['FileOrString', 'build.GeneratedTypes', build.BuildTarget, build.StructuredSources]] = []
+        depends.extend(gir_dep.sources)
         depends.extend(girtargets)
 
         langs_compilers = self._get_girtargets_langs_compilers(girtargets)
         cflags, internal_ldflags, external_ldflags = self._get_langs_compilers_flags(state, langs_compilers)
         deps = self._get_gir_targets_deps(girtargets)
         deps += kwargs['dependencies']
-        deps += [state.dependency('glib-2.0'), state.dependency('gobject-2.0'), state.dependency('gmodule-2.0'), state.dependency('gio-2.0')]
+        deps += [gir_dep]
         typelib_includes, depends = self._gather_typelib_includes_and_update_depends(state, deps, depends)
         # ldflags will be misinterpreted by gir scanner (showing
         # spurious dependencies) but building GStreamer fails if they