gfxstream: explicitly list Python dependencies for gfxstream codegen

This helps Meson track when dependencies are modified.  If they
are modified, running ninja -C actually re-generates the code.
Beforehand, this was not the case and contrary to the user
expectation.

Reviewed-by: David Gilhooley <djgilhooley.gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/39205>

src/gfxstream/codegen/scripts/meson.build

@@ -0,0 +1,35 @@
+# Copyright © 2026 Google
+# SPDX-License-Identifier: MIT
+
+genvk = files('genvk.py')
+
+genvk_depends = files(
+    'cereal/__init__.py',
+    'cereal/api_log_decoder.py',
+    'cereal/common/__init__.py',
+    'cereal/common/codegen.py',
+    'cereal/common/vulkantypes.py',
+    'cereal/counting.py',
+    'cereal/decoder.py',
+    'cereal/decodersnapshot.py',
+    'cereal/deepcopy.py',
+    'cereal/dispatch.py',
+    'cereal/encoder.py',
+    'cereal/extensionstructs.py',
+    'cereal/frontend.py',
+    'cereal/functable.py',
+    'cereal/handlemap.py',
+    'cereal/marshaling.py',
+    'cereal/marshalingdefs.py',
+    'cereal/reservedmarshaling.py',
+    'cereal/subdecode.py',
+    'cereal/testing.py',
+    'cereal/transform.py',
+    'cereal/unbox.py',
+    'cereal/vkextensionstructuretype.py',
+    'cereal/wrapperdefs.py',
+    'cerealgenerator.py',
+    'cgenerator.py',
+    'generator.py',
+    'reg.py',
+)

src/gfxstream/guest/vulkan_enc/meson.build

@@ -24,6 +24,7 @@ if build_machine.system() != 'android'
             'VkEncoder.cpp',
             'func_table.cpp',
         ],
+        depend_files: genvk_depends,
         env: {
             'GFXSTREAM_NO_CLANG_FMT': '1',
             'CEREAL_VARIANT' : 'guest',
@@ -48,6 +49,7 @@ if build_machine.system() != 'android'
         output: ['vulkan_gfxstream.h'],
         env: {'GFXSTREAM_NO_CLANG_FMT': '1', 'CEREAL_VARIANT' : 'guest'},
         input: [genvk, vk_gfxstream_xml],
+        depend_files: genvk_depends,
         command: [
             prog_python,
             '@INPUT0@',

src/gfxstream/meson.build

@@ -1,8 +1,8 @@
 # Copyright © 2024 Google
 # SPDX-License-Identifier: MIT
 
-genvk = files('codegen/scripts/genvk.py')
 vk_gfxstream_xml = files('codegen/xml/vk_gfxstream.xml')
 
 subdir('aemu')
+subdir('codegen/scripts')
 subdir('guest')