Remove syncfs fallback for ancient glibc (Debian 7)

qrexec-lib/unpack.c

@@ -33,10 +33,6 @@ void send_status_and_crc(int code, const char *last_filename);
 #define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT)
 #endif
 
-#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 14)
-#define HAVE_SYNCFS
-#endif
-
 void do_exit(int code, const char *last_filename)
 {
     close(0);
@@ -213,10 +209,8 @@ void process_one_file(struct file_header *untrusted_hdr)
 int do_unpack(void)
 {
     struct file_header untrusted_hdr;
-#ifdef HAVE_SYNCFS
     int cwd_fd;
     int saved_errno;
-#endif
 
     total_bytes = total_files = 0;
     /* initialize checksum */
@@ -233,14 +227,10 @@ int do_unpack(void)
         process_one_file(&untrusted_hdr);
     }
 
-#ifdef HAVE_SYNCFS
     saved_errno = errno;
     cwd_fd = open(".", O_RDONLY);
     if (cwd_fd >= 0 && syncfs(cwd_fd) == 0 && close(cwd_fd) == 0)
         errno = saved_errno;
-#else
-    sync();
-#endif
 
     send_status_and_crc(errno, untrusted_namebuf);
     return errno;