Avoid defining constants which causes at least dpkg build to think that
sync_file_range(2) is available - which it is not.

diff -u -r /home/fornwall/lib/android-ndk/sysroot/usr/include/fcntl.h ./usr/include/fcntl.h
--- /home/fornwall/lib/android-ndk/sysroot/usr/include/fcntl.h	2017-06-07 01:07:52.000000000 +0200
+++ ./usr/include/fcntl.h	2017-06-18 02:03:25.533276409 +0200
@@ -61,10 +61,6 @@
 #define SPLICE_F_MORE 4
 #define SPLICE_F_GIFT 8
 
-#define SYNC_FILE_RANGE_WAIT_BEFORE 1
-#define SYNC_FILE_RANGE_WRITE 2
-#define SYNC_FILE_RANGE_WAIT_AFTER 4
-
 int creat(const char*, mode_t);
 
 #if __ANDROID_API__ >= 21