tests/file_ioctl.c: fix build on systems without <linux/fiemap.h>

* tests/file_ioctl.c: Include "tests.h" first.
Skip the test if [!HAVE_LINUX_FIEMAP_H].
diff --git a/tests/file_ioctl.c b/tests/file_ioctl.c
index 3264b90..e8950df 100644
--- a/tests/file_ioctl.c
+++ b/tests/file_ioctl.c
@@ -1,11 +1,13 @@
-#include <stdio.h>
-#include <sys/ioctl.h>
-#include <linux/fiemap.h>
-#include <linux/fs.h>
 #include "tests.h"
-#include "xlat.h"
 
-#include "xlat/fiemap_flags.h"
+#ifdef HAVE_LINUX_FIEMAP_H
+
+# include <stdio.h>
+# include <sys/ioctl.h>
+# include <linux/fiemap.h>
+# include <linux/fs.h>
+# include "xlat.h"
+# include "xlat/fiemap_flags.h"
 
 static void
 test_fiemap(void)
@@ -31,3 +33,9 @@
 
 	return 0;
 }
+
+#else
+
+SKIP_MAIN_UNDEFINED("HAVE_LINUX_FIEMAP_H")
+
+#endif