diff --git a/src/m/hp9000s300.h b/src/m/hp9000s300.h
index c541643ded8..6979e1a51da 100644
--- a/src/m/hp9000s300.h
+++ b/src/m/hp9000s300.h
@@ -161,6 +161,10 @@ NOTE-END */
 
 #define LOAD_AVE_CVT(x) ((int) ((x) * 100.0))
 
+#ifdef __GNUC__
+#define HAVE_ALLOCA
+#endif
+
 /* This library is needed with -g, on the 200/300 only.  */
 
 #if !defined(__GNUC__) || defined(__HPUX_ASM__)