Change assets to use 64-bit API

The asset system and supporting libraries were using off_t instead of
off64_t to access files larger than 2GB (32-bit signed). This change
replaces all off_t with off64_t and lseek64.

There is a new utils/Compat.h added for Mac OS compatibility.

Also fixed some size-related compiler warnings.

Bug: 3205336
Change-Id: I9097b3cb7a602e811fe52f245939d8975da55e9e
diff --git a/libs/utils/ZipFileCRO.cpp b/libs/utils/ZipFileCRO.cpp
index 16b219c..55dfd9f 100644
--- a/libs/utils/ZipFileCRO.cpp
+++ b/libs/utils/ZipFileCRO.cpp
@@ -40,7 +40,7 @@
 
 bool ZipFileCRO_getEntryInfo(ZipFileCRO zipToken, ZipEntryRO entryToken,
         int* pMethod, size_t* pUncompLen,
-        size_t* pCompLen, off_t* pOffset, long* pModWhen, long* pCrc32) {
+        size_t* pCompLen, off64_t* pOffset, long* pModWhen, long* pCrc32) {
     ZipFileRO* zip = (ZipFileRO*)zipToken;
     ZipEntryRO entry = (ZipEntryRO)entryToken;
     return zip->getEntryInfo(entry, pMethod, pUncompLen, pCompLen, pOffset,