meson: Use build_always_stale instead of build_always

which was deprecated in 0.47. This doesn't change behavior, just shuts
up warnings.

meson.build:105: WARNING: Project targets '>= 1.4.0' but uses feature deprecated since '0.47.0': build_always arg in custom_target. combine build_by_default and build_always_stale instead.

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Reviewed-by: Pohsiang (John) Hsu <pohhsu@microsoft.com>
Reviewed-by: Eric Engestrom <eric@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36891>

src/gallium/frontends/mediafoundation/meson.build

@@ -105,7 +105,8 @@ endforeach
 mediafoundation_wpp_preprocess = custom_target(
   'mediafoundation_wpp_preprocess',
   capture : true,
-  build_always: true,
+  build_by_default : true,
+  build_always_stale : true,
   input : mediafoundation_files,
   output : 'mediafoundation_wpp_preprocess.dummy.h',
   command : ['tracewpp', '-cfgdir:@CURRENT_SOURCE_DIR@/wppconfig/rev1', '-scan:@CURRENT_SOURCE_DIR@/wpptrace.h', '-odir:@OUTDIR@', '@' + fs.relative_to(mediafoundation_wpp_rsp, 'a:\\')]

src/mesa/meson.build

@@ -10,7 +10,8 @@ if _shader_replacement != ''
     input: [files(_shader_replacement + '/process_shaders.py')],
     output: 'shader_replacement.h',
     command: [prog_python, '@INPUT0@', _shader_replacement, '@OUTPUT@'],
-    build_always: true,
+    build_by_default : true,
+    build_always_stale : true,
   )
 endif