new cheesy test by Denis Vlasenko to trigger fclose loop

test/stdio/fclose-loop.c

@@ -0,0 +1,21 @@
+/* From: Denis Vlasenko <vda.linux@googlemail.com>
+ *	With certain combination of .config options fclose() does not
+ *	remove FILE* pointer from _stdio_openlist.  As a result, subsequent
+ *	fopen() may allocate new FILE structure exactly in place of one
+ *	freed by previous fclose(), which then makes _stdio_openlist
+ *	circularlt looped. The following program will enter infinite loop
+ *	trying to walk _stdio_openlist in exit():
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(int argc, char *argv[])
+{
+	FILE* fp;
+	fp = fopen("/dev/null", "r");
+	fclose(fp);
+	fp = fopen("/dev/zero", "r");
+	fclose(fp);
+	return 0;
+}