qapi: Fix C identifiers generated for names containing '.'

c_fun() maps '.' to '_', c_var() doesn't.  Nothing prevents '.' in
QAPI names that get passed to c_var().

Which QAPI names get passed to c_fun(), to c_var(), or to both is not
obvious.  Names of command parameters and struct type members get
passed to c_var().

c_var() strips a leading '*', but this cannot happen.  c_fun()
doesn't.

Fix c_var() to work exactly like c_fun().

Perhaps they should be replaced by a single mapping function.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
[add 'import string']
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>

scripts/qapi.py

@@ -15,6 +15,7 @@ import re
 from ordereddict import OrderedDict
 import os
 import sys
+import string
 
 builtin_types = {
     'str':      'QTYPE_QSTRING',
@@ -752,6 +753,8 @@ def camel_case(name):
             new_name += ch.lower()
     return new_name
 
+c_var_trans = string.maketrans('.-', '__')
+
 def c_var(name, protect=True):
     # ANSI X3J11/88-090, 3.1.1
     c89_words = set(['auto', 'break', 'case', 'char', 'const', 'continue',
@@ -781,10 +784,10 @@ def c_var(name, protect=True):
     polluted_words = set(['unix', 'errno'])
     if protect and (name in c89_words | c99_words | c11_words | gcc_words | cpp_words | polluted_words):
         return "q_" + name
-    return name.replace('-', '_').lstrip("*")
+    return name.translate(c_var_trans)
 
 def c_fun(name, protect=True):
-    return c_var(name, protect).replace('.', '_')
+    return c_var(name, protect)
 
 def c_list_type(name):
     return '%sList' % name