--- heroes-0.21/configure.ac
+++ heroes-0.21/configure.ac
@@ -112,7 +112,7 @@
 # Checks for typedefs, structures, and compiler characteristics.
 # ==============================================================
 
-AM_C_PROTOTYPES
+AC_C_PROTOTYPES
 AC_C_CONST
 AC_TYPE_UID_T     dnl This checks for gid_t too.
 AC_CHECK_TYPES([ssize_t])