macOS build fix: no off64_t on darwin.

Darwin has always had a 64-bit off_t, and never added an off64_t.

Test: builds on mac
Change-Id: I4b244dda94c67da76c9e0f47b333c2734f5a94af

adb/client/incremental_utils.h

@@ -25,6 +25,8 @@
 
 #include <stdint.h>
 
+#include <android-base/off64_t.h>
+
 namespace incremental {
 
 using Size = int64_t;