qapi: change the type of TargetInfo.arch from string to enum SysEmuTarget

Now that we have @SysEmuTarget, it makes sense to restrict
@TargetInfo.@arch to valid sysemu targets at the schema level.

Cc: "Daniel P. Berrange" <berrange@redhat.com>
Cc: Eric Blake <eblake@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180427192852.15013-4-lersek@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

arch_init.c

@@ -29,6 +29,7 @@
 #include "hw/pci/pci.h"
 #include "hw/audio/soundhw.h"
 #include "qapi/qapi-commands-misc.h"
+#include "qapi/error.h"
 #include "qemu/config-file.h"
 #include "qemu/error-report.h"
 #include "hw/acpi/acpi.h"
@@ -112,7 +113,8 @@ TargetInfo *qmp_query_target(Error **errp)
 {
     TargetInfo *info = g_malloc0(sizeof(*info));
 
-    info->arch = g_strdup(TARGET_NAME);
+    info->arch = qapi_enum_parse(&SysEmuTarget_lookup, TARGET_NAME, -1,
+                                 &error_abort);
 
     return info;
 }

qapi/misc.json

@@ -5,6 +5,8 @@
 # = Miscellanea
 ##
 
+{ 'include': 'common.json' }
+
 ##
 # @qmp_capabilities:
 #
@@ -2449,12 +2451,12 @@
 #
 # Information describing the QEMU target.
 #
-# @arch: the target architecture (eg "x86_64", "i386", etc)
+# @arch: the target architecture
 #
 # Since: 1.2.0
 ##
 { 'struct': 'TargetInfo',
-  'data': { 'arch': 'str' } }
+  'data': { 'arch': 'SysEmuTarget' } }
 
 ##
 # @query-target: