meson: Add TARGET_ARCH to config_target_data

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20260205030617.266625-3-richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

meson.build

@@ -3263,7 +3263,7 @@ host_kconfig = \
   (hv_balloon ? ['CONFIG_HV_BALLOON_POSSIBLE=y'] : []) + \
   (have_rust ? ['CONFIG_HAVE_RUST=y'] : [])
 
-ignored = [ 'TARGET_XML_FILES', 'TARGET_ABI_DIR', 'TARGET_ARCH' ]
+ignored = [ 'TARGET_XML_FILES', 'TARGET_ABI_DIR' ]
 
 default_targets = 'CONFIG_DEFAULT_TARGETS' in config_host
 actual_target_dirs = []
@@ -3353,6 +3353,8 @@ foreach target : target_dirs
       # do nothing
     elif ignored.contains(k)
       # do nothing
+    elif k == 'TARGET_ARCH'
+      config_target_data.set(k, v.to_upper())
     elif k == 'TARGET_BASE_ARCH'
       # Note that TARGET_BASE_ARCH ends up in config-target.h but it is
       # not used to select files from sourcesets.