Add SEEK_DATA and SEEK_HOLE constants.
Without pulling in <linux/fs.h>, the UAPI source of these constants,
because it's full of pollution, in particular a macro called BLOCK_SIZE
that breaks a lot of stuff.
Test: treehugger
Change-Id: I7258ec57e91c67645c2b4d0ce44850d757c4bb12
diff --git a/libc/include/bits/seek_constants.h b/libc/include/bits/seek_constants.h
index 6b88606..6f3f22d 100644
--- a/libc/include/bits/seek_constants.h
+++ b/libc/include/bits/seek_constants.h
@@ -39,3 +39,23 @@
#define SEEK_CUR 1
/** Seek relative to the end of the file. */
#define SEEK_END 2
+
+#if defined(__USE_GNU)
+
+/**
+ * Seek to the first data (non-hole) location in the file
+ * greater than or equal to the given offset.
+ *
+ * See [lseek(2)](http://man7.org/linux/man-pages/man2/lseek.2.html).
+ */
+#define SEEK_DATA 3
+
+/**
+ * Seek to the first hole (non-data) location in the file
+ * greater than or equal to the given offset.
+ *
+ * See [lseek(2)](http://man7.org/linux/man-pages/man2/lseek.2.html).
+ */
+#define SEEK_HOLE 4
+
+#endif