tests: workaround broken awk

* tests/getdents.out: New file.
* tests/Makefile.am (EXTRA_DIST): Add it.
* tests/getdents.test: Check whether awk is capable of matching long
regular expressions.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 08d7a4d..98ae2d5 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -86,6 +86,7 @@
 	     caps.awk \
 	     dumpio.expected \
 	     getdents.awk \
+	     getdents.out \
 	     mmsg.expected \
 	     net-yy-accept.awk \
 	     net-yy-connect.awk \