Unify zipfile implementations : Step 1.

Extract zip file processing logic from libdvm into a
standalone library.

This library is a stricter than the libdvm library in
several ways:
- Duplicate zip entry names are now disallowed. Files with
  such entries will fail to parse.
- We now verify CD file size information with the individual
  file header information. (This was pointed out as a deficiency
  of this implementation in past discussions.)
- We also add support for crc checking, which means we might
  need to parse the optional data descriptor footer (if one
  exists).

We also provide an API for iterating over the entries of
a zip file. This library is optimized for two use cases :

- Lookup for a single entry in the file, with the intention
  of processing or extracting the data associated with that
  entry
- Iterating over all entries in a file *and* processing
  / extracting their data.

Change-Id: Ia87de6184ef753cc470b0af755c47a4f92ac8198
Fix Mac OS build for libziparchive.

BSD off_t are implicitly 64 bit so the platform
doesn't define off64_t.

Change-Id: I51cbe94ead01d2d6bc7c5010d9472487bee7c2d3
Fix return code for ended iteration.

The API promises a return code of -1 for an
ended iteration and lower negative values for
errors.

Change-Id: I688a1ee2efad1bdfc6959cf27e49c0426ebf27f8
Add unit tests for libziparchive.

- Add a build rule for host tests
- Add basic tests for Find / Iterate and Extract
  for both deflated & stored entries.
- Fix an off by one error that the test uncovered.

Change-Id: If72009b1ea9791d5a265829f05c32ffe1c2752c4
Use FileMap from libcutil instead of rolling our own.

Adds windows support as a side effect.

Change-Id: I912c1f980f284d01d4f3936291999646ddf6250a
Get rid of some log spam.

We don't need a warning if an entry isn't found in a zip
file. It can happen as part of normal operation.

Change-Id: I86c132a040371f36f0dd981b49c02b3173821439
Fix ExtractEntryToFile.

We would always write uncompressed data at offset 0 instead
of the current filedescriptor offset.

Also adds a unit-test & a clarifying comment on the API.

Change-Id: If44757e96dde504ce63d81b4dec7115fc6f6d5fb
Fix a sporadic build breakage.

The issue here is that the makefile sets LOCAL_LDFLAGS
and asks for -llog without declaring a dependency on it.
This will cause build breakages if liblog hasn't already
been built yet.

Change-Id: Ia38761cda44a38b6c2a88902d6108cbe64a328ce
Fix entry handling for 0 length entries.

Two minor issues were fixed:
- The offset to entry data can be the same as the
  central directory offset when the last entry in the
  file has length 0 and is stored (not deflated). Fix
  a check that disallowed this. We already have a strict
  check that entry data must end before the central directory,
  so we're covered.
- We would attempt to map a segment of length 0 when writing
  an entry whose length is 0. We should just return early in
  this case.

bug: 12623277
Change-Id: I2a4ca0c4d170cc3cbf326e5ca13894acd9c434c9
Add free to CloseArchive.

Currently CloseArchive doesn't call free and call sites don't appear
to either. I could not find any call sites which manually freed the
archive by deleting the handle. This fixes several memory leaks.

Change-Id: I21f187dde60fd87e6e54bde06de9e76fd0791104