diff --git a/gdb/config/sparc/xm-sun4sol2.h b/gdb/config/sparc/xm-sun4sol2.h
index 0ec436fe1e..2714909882 100644
--- a/gdb/config/sparc/xm-sun4sol2.h
+++ b/gdb/config/sparc/xm-sun4sol2.h
@@ -65,3 +65,7 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
 
 /* Solaris PSRVADDR support does not seem to include a place for nPC.  */
 #define PRSVADDR_BROKEN
+
+/* The mem functions are in <string.h>.  */
+#undef MEM_FNS_DECLARED
+#define MEM_FNS_DECLARED 1