portability: add sys/sysmacros.h wrapper for makedev/major/minor

portability/sys/sysmacros.h

@@ -0,0 +1,9 @@
+#ifdef __linux__
+# include_next <sys/sysmacros.h>
+#else
+# include <stdint.h>
+# include <sys/types.h>
+# define major(x)        ((int32_t)(((u_int32_t)(x) >> 24) & 0xff))
+# define minor(x)        ((int32_t)((x) & 0xffffff))
+# define makedev(x, y)    ((dev_t)(((x) << 24) | (y)))
+#endif