disable sync_file_range for now

something is wrong with the logic for the argument layout, resulting
in compile errors on mips due to too many args to syscall... further
information on how it's supposed to work will be needed before it can
be reactivated.

src/linux/sync_file_range.c

 #define _GNU_SOURCE
 #include <fcntl.h>
+#include <errno.h>
 #include "syscall.h"
 
 int sync_file_range(int fd, off_t pos, off_t len, unsigned flags)
 {
-#if defined(SYS_sync_file_range2)
+#if 0 && defined(SYS_sync_file_range2)
 	return syscall(SYS_sync_file_range2, fd, flags,
 		__SYSCALL_LL_E(pos), __SYSCALL_LL_E(len));
-#elif defined(SYS_sync_file_range)
+#elif 0 && defined(SYS_sync_file_range)
 	return syscall(SYS_sync_file_range, fd,
 		__SYSCALL_LL_O(pos), __SYSCALL_LL_E(len), flags);
 #else