This patch is part of a bigger patch that helps merging the breakpad code
with the modified version in Chromium OS.
Specifically, this patch makes the following changes:
1. Add a SafeReadLink function that wraps sys_readlink() to resolve a
symbolic link but guarantees the result is NULL-terminated on success.
2. Refactor other source code to use SafeReadLink instead of readlink()
or sys_readlink().
BUG=455
TEST=Tested the following:
1. Build on 32-bit and 64-bit Linux with gcc 4.4.3 and gcc 4.6.
2. Build on Mac OS X 10.6.8 with gcc 4.2 and clang 3.0 (with latest gmock).
3. All unit tests pass.
4. Run minidump-2-core to covnert a minidump file to a core file.
Review URL: http://breakpad.appspot.com/334001
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@896 4c0a9323-5329-0410-9bdc-e9ce6186880e
