tests: add uname.test

* tests/uname.c: New file.
* tests/uname.test: New test.
* tests/.gitignore: Add uname.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(TESTS): Add uname.test.
diff --git a/tests/.gitignore b/tests/.gitignore
index bdce2db..e79d317 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -124,6 +124,7 @@
 umount2
 umovestr
 umovestr2
+uname
 unix-pair-send-recv
 userfaultfd
 utime