Define __EXTENSIONS__ on Solaris. Fixes posixmodule error in bug #232787.
diff --git a/acconfig.h b/acconfig.h
index 045e454..3f7829f 100644
--- a/acconfig.h
+++ b/acconfig.h
@@ -25,6 +25,9 @@
 /* Define to `long' if <time.h> doesn't define.  */
 #undef clock_t
 
+/* Defined on Solaris to see additional function prototypes. */
+#undef __EXTENSIONS__
+
 /* Define if getpgrp() must be called as getpgrp(0). */
 #undef GETPGRP_HAVE_ARG