tests: add fsync.test

* tests/fsync.c: New file.
* tests/fsync.test: New test.
* tests/.gitignore: Add fsync.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add fsync.test.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 98be3a4..4d18fe6 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -93,6 +93,7 @@
 	fstat \
 	fstat64 \
 	fstatat64 \
+	fsync \
 	ftruncate \
 	ftruncate64 \
 	getcwd \
@@ -276,6 +277,7 @@
 	fstat.test \
 	fstat64.test \
 	fstatat64.test \
+	fsync.test \
 	ftruncate.test \
 	ftruncate64.test \
 	getcwd.test \