Try to use the int32 and friends on all Unixes -- not just SGI's Irix.
--- ../include/icc34.h	Tue Feb 13 12:08:06 2001
+++ ../include/icc34.h	Wed Sep  5 10:08:42 2001
@@ -144,7 +144,9 @@
  */

+#ifdef __unix__
 #ifdef __sgi
 #include "sgidefs.h"
+#endif
 
 typedef __int32_t	icSignature;