fastboot driver: ftrucate64->ftruncate.

Also, -D_FILE_OFFSET_BITS=64 so that off_t is always
64 bits.

This fixes mac build.

Test: forrest

Change-Id: I584e136a5f3ca9874fd5364cc4c93f8b1e8feb19
diff --git a/fastboot/Android.bp b/fastboot/Android.bp
index bf9ec90..43b2ddd 100644
--- a/fastboot/Android.bp
+++ b/fastboot/Android.bp
@@ -208,6 +208,7 @@
         "-Werror",
         "-Wunreachable-code",
         "-DANDROID_BASE_UNIQUE_FD_DISABLE_IMPLICIT_CONVERSION",
+        "-D_FILE_OFFSET_BITS=64"
     ],
 
     target: {