diff --git a/python_modules/marshal.py b/python_modules/marshal.py
index cc6cbdf..dc36e18 100644
--- a/python_modules/marshal.py
+++ b/python_modules/marshal.py
@@ -1,13 +1,22 @@
 
 from . import ptypes
 from . import codegen
+import re
 
 def write_includes(writer):
     writer.header.writeln("#include <spice/protocol.h>")
     writer.header.writeln('#include "common/marshaller.h"')
     writer.header.newline()
-    writer.header.writeln("#ifndef _GENERATED_HEADERS_H")
-    writer.header.writeln("#define _GENERATED_HEADERS_H")
+    if writer.header.has_option("dest_file"):
+        src = writer.header.options["dest_file"]
+    else:
+        src = "generated_headers.h"
+    src = re.sub(r'[^a-z0-9]+', '_', src, flags=re.IGNORECASE)
+    src = src.upper()
+    if src.endswith("_H"):
+        src = "_H_"+src[:-2]
+    writer.header.writeln("#ifndef %s" % src)
+    writer.header.writeln("#define %s" % src)
 
     writer.writeln("#include <string.h>")
     writer.writeln("#include <assert.h>")
diff --git a/spice_codegen.py b/spice_codegen.py
index c019ad8..410acbd 100755
--- a/spice_codegen.py
+++ b/spice_codegen.py
@@ -170,6 +170,7 @@ if proto == None:
 codegen.set_prefix(proto.name)
 writer = codegen.CodeWriter()
 writer.header = codegen.CodeWriter()
+writer.header.set_option("dest_file", dest_file)
 writer.set_option("source", os.path.basename(proto_file))
 
 license = """/*