missing: add more compat for old kernels and loop devices

https://bugs.freedesktop.org/show_bug.cgi?id=76335

src/shared/missing.h

@@ -32,6 +32,7 @@
 #include <linux/oom.h>
 #include <linux/input.h>
 #include <linux/if_link.h>
+#include <linux/loop.h>
 
 #ifdef HAVE_AUDIT
 #include <libaudit.h>
@@ -369,3 +370,11 @@ static inline int setns(int fd, int nstype) {
 #if !HAVE_DECL_LO_FLAGS_PARTSCAN
 #define LO_FLAGS_PARTSCAN 8
 #endif
+
+#ifndef LOOP_CTL_REMOVE
+#define LOOP_CTL_REMOVE 0x4C81
+#endif
+
+#ifndef LOOP_CTL_GET_FREE
+#define LOOP_CTL_GET_FREE 0x4C82
+#endif