--- a/wscript_configure_embedded_heimdal
+++ b/wscript_configure_embedded_heimdal
@@ -6,3 +6,14 @@ if not conf.env['BISON']:
 
 conf.define('USING_EMBEDDED_HEIMDAL', 1)
 conf.RECURSE('third_party/heimdal_build')
+
+def check_system_heimdal_binary(name):
+    if conf.LIB_MAY_BE_BUNDLED(name):
+        return False
+    if not conf.find_program(name, var=name.upper()):
+        return False
+    conf.define('USING_SYSTEM_%s' % name.upper(), 1)
+    return True
+
+check_system_heimdal_binary("compile_et")
+check_system_heimdal_binary("asn1_compile")