diff --git a/dtool/Config.Irix.pp b/dtool/Config.Irix.pp
index 515b29d3e2..45edc47183 100644
--- a/dtool/Config.Irix.pp
+++ b/dtool/Config.Irix.pp
@@ -90,3 +90,6 @@
 // Do we have <sys/soundcard.h> (and presumably a Linux-style audio
 // interface)?
 #define HAVE_SYS_SOUNDCARD_H
+
+// Do we have RTTI (and <typeinfo>)?
+#define HAVE_RTTI 1
diff --git a/dtool/Config.Linux.pp b/dtool/Config.Linux.pp
index 6355817bc4..f929041c46 100644
--- a/dtool/Config.Linux.pp
+++ b/dtool/Config.Linux.pp
@@ -90,3 +90,6 @@
 // Do we have <sys/soundcard.h> (and presumably a Linux-style audio
 // interface)?
 #define HAVE_SYS_SOUNDCARD_H 1
+
+// Do we have RTTI (and <typeinfo>)?
+#define HAVE_RTTI 1
diff --git a/dtool/Config.Win32.pp b/dtool/Config.Win32.pp
index fbb5f2e007..670f7a3727 100644
--- a/dtool/Config.Win32.pp
+++ b/dtool/Config.Win32.pp
@@ -91,6 +91,9 @@
 // interface)?
 #define HAVE_SYS_SOUNDCARD_H
 
+// Do we have RTTI (and <typeinfo>)?
+#define HAVE_RTTI 1
+
 // can Intel C++ build this directory successfully (if not, change CC to msvc)
 #define NOT_INTEL_BUILDABLE false
 
diff --git a/dtool/LocalSetup.pp b/dtool/LocalSetup.pp
index e45584c63e..8a769d66fc 100644
--- a/dtool/LocalSetup.pp
+++ b/dtool/LocalSetup.pp
@@ -171,6 +171,9 @@ $[cdefine HAVE_DIRENT_H]
    interface)? */
 $[cdefine HAVE_SYS_SOUNDCARD_H]
 
+/* Do we have RTTI (and <typeinfo>)? */
+$[cdefine HAVE_RTTI]
+
 #end dtool_config.h
 
 #endif   // BUILD_TYPE