diff --git a/build/bakefiles/formats/__fake.bkl b/build/bakefiles/formats/__fake.bkl
index 21a852076e..704b4dd37f 100644
--- a/build/bakefiles/formats/__fake.bkl
+++ b/build/bakefiles/formats/__fake.bkl
@@ -23,6 +23,8 @@ makefiles, e.g. wx24dsp or rpmspec ones.
         <define-tag name="optimize"/>
         <define-tag name="warnings"/>
         <define-tag name="threading"/>
+        <define-tag name="cxx-rtti"/>
+        <define-tag name="cxx-exceptions"/>
         <define-tag name="cppflags"/>
         <define-tag name="cflags"/>
         <define-tag name="cxxflags"/>