qapi: De-duplicate parameter list generation

Generated qapi-event.[ch] lose line breaks.  No change otherwise.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-18-git-send-email-armbru@redhat.com>
diff --git a/scripts/qapi.py b/scripts/qapi.py
index 7ac72f6..6b6f1ae 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -1469,6 +1469,22 @@
                  c_name=c_name(name))
     return ret
 
+def gen_params(arg_type, extra):
+    if not arg_type:
+        return extra
+    assert not arg_type.variants
+    ret = ''
+    sep = ''
+    for memb in arg_type.members:
+        ret += sep
+        sep = ', '
+        if memb.optional:
+            ret += 'bool has_%s, ' % c_name(memb.name)
+        ret += '%s %s' % (memb.type.c_type(is_param=True), c_name(memb.name))
+    if extra:
+        ret += sep + extra
+    return ret
+
 #
 # Common command line parsing
 #