Add unit test for tempfile()

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

tests/tempfile.c

@@ -0,0 +1,25 @@
+#include <fcntl.h>		/* O_TMPFILE requires -D_GNU_SOURCE */
+#include <paths.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "check.h"
+
+#ifndef  O_TMPFILE
+#warning O_TMPFILE is missing, either too old GLIBC, Linux, or non-Linux system
+#endif
+
+int main(void)
+{
+	FILE *fp;
+
+	printf("Before tempfile():\n");
+	system("ls -lrt " _PATH_TMP " | tail -3");
+
+	fp = tempfile();
+	fail_unless(fp != NULL);
+
+	printf("\nAfter tempfile(), should be same list:\n");
+	system("ls -lrt " _PATH_TMP " | tail -3");
+
+	return fclose(fp);
+}