meson: Fix enum types generation to match automake

The automake generated ones are a little funky, so the meson one have to also be
to not break API...

agent/meson.build

@@ -27,12 +27,22 @@ agent_sources = files([
 
 gnome = import('gnome')
 
-agent_enum_types = gnome.mkenums_simple('agent-enum-types', sources : agent_headers)
-agent_enum_types_c = agent_enum_types[0]
-agent_enum_types_h = agent_enum_types[1]
+agent_enum_types_c =  gnome.mkenums('agent-enum-types.c', sources : agent_headers,
+				    fhead: '#include <config.h>\n#include <glib-object.h>\n#include "agent.h"\n#include "pseudotcp.h"\n#include "agent-enum-types.h"',
+				    fprod: '\n/* enumerations from "@filename@" */',
+				    vhead: 'GType\n@enum_name@_get_type (void)\n{\n  static GType type = 0;\n  if (!type) {\n    static const G@Type@Value values[] = {',
+				    vprod: '      { @VALUENAME@, "@VALUENAME@", "@valuenick@" },',
+				    vtail: '      { 0, NULL, NULL }\n    };\n    type = g_@type@_register_static ("@EnumName@", values);\n  }\n  return type;\n}\n\n')
+
+agent_enum_types_h = gnome.mkenums('agent-enum-types.h', sources : agent_headers,
+				   fhead: '#ifndef __AGENT_ENUM_TYPES_H__\n#define __AGENT_ENUM_TYPES_H__ 1\n\n#include <glib-object.h>\n\nG_BEGIN_DECLS\n',
+				   fprod: '/* enumerations from "@filename@" */\n',
+				   vhead: 'GType @enum_name@_get_type (void) G_GNUC_CONST;\n#define NICE_TYPE_@ENUMSHORT@ (@enum_name@_get_type())\n',
+					  ftail: 'G_END_DECLS\n\n#endif /* !AGENT_ENUM_TYPES_H */')
+
 
 libagent = static_library('agent',
-  agent_enum_types, agent_sources,
+  agent_enum_types_c, agent_enum_types_h, agent_sources,
   c_args: ['-DG_LOG_DOMAIN="libnice"'],
   include_directories: nice_incs,
   dependencies: nice_deps,