Use libunwind as an imported target

* Added fixed log name support, take 2

See https://code.google.com/p/google-glog/issues/detail?id=209 and former https://github.com/google/glog/pull/19 - this is an updated version of that patch.

It adds a flag that allows to switch behavior from base_filename + filename_extension + time_pid_string to base_filename + filename_extension, while still defaulting to the current behavior to avoid breakage in existing code. This change would allow easier log rotation schemes and better control on what's written on disk.

* Ifdef away fcntl on mingw

* Use the defined HAVE_FCNTL instead

* ifdef away tests as well

add have_sys_wait for wait() on mingw.

* OS_WINDOWS bug in fseeking to the end, only triggered here

doc: add information about log cleaner

src/logging.cc: fix wrong assignment

src/symbolize.cc: do not check for HAVE_DLFCN_H for macOS

This seems to raise a build failure, see
https://github.com/google/glog/commit/10498b485fe1007f8e913bf2c39ff39fe01c8dc8#commitcomment-35770392Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

src/utilities: fix build without pthread

When UNWIND_LIBRARY is used directly as a public dependency then
absolute path is stored in cmake config file. This is an issue when
glog is used as part of an SDK, which was built somewhere else. When
SDK is installed on developer's machine, cmake config contains a full
path to non-existent location. The solution is to find libunwind
during configure stage and store target name as a dependency, not a full path.
Cmake module looks for libunwind and libunwind-PLAT, where PLAT is one of
supported platforms.
Signed-off-by: Vyacheslav Yurkov <uvv.mail@gmail.com>

- Remove is_default_thread function which is an internal and not used
  function
- Remove g_main_thread_id as it was used only by is_default_thread

Fixes:
 - http://autobuild.buildroot.net/results/5320bbe1205e782e3516d9bead8d1ed825bcbaadSigned-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

removed executable flag from .cmake file

Support pkg-config

Revert "Added fixed log name support"

* Add support for automatic removal of old logs

GetOverdueLogNames(string log_directory, int days) will check all
filenames under log_directory, and return a list of files whose last modified time is
over the given days (calculated using difftime()).

So that we can easily for unlink all files stored in the returned vector.

* Replaced the lines that require C++11

* embed dirent.h in project

* Add support for automatic removal of old logs

In this commit, at the end of LogFileObject::Write,
it will perform clean up for old logs.

It uses GetLoggingDirectories() and for each file in each
directory, it will check if a file is a log file produced by glog.
If it is, and it is last modified 3 days ago, then it will unlink()
this file. (It will only remove the project's own log files,
it won't remove the logs from other projects.)

Currently it is hardcoded to 3 days, I'll see if this can be
implemented in a more flexible manner.

* Implement old log cleaner

The log cleaner can be enabled and disabled at any given time.
By default, the log cleaner is disabled.

For example, this will enable the log cleaner and delete
the log files whose last modified time is >= x days
google::EnableLogCleaner(x days);

To disable it, simply call
google::DisableLogCleaner();

Please note that it will only clean up the logs produced for
its own project, the log files from other project will be untouched.

* logging: log_cleaner: Use blackslash for windows dir delim

* logging: log_cleaner: remove the range-based loops

Also replaced the hardcoded overdue days with the correct variable.

* Add Marco Wang to AUTHORS and CONTRIBUTORS

* logging: log_cleaner: Remove redundant filename stripping

Previously the full path to a file is passed into IsGlogLog(),
and then std::string::erase() is used to get the filename part.
If a directory name contains '.', then this function will be unreliable.

Now only the filename it self is passed into IsGlogLog(),
so this problem will be eradicated.

* logging: log_cleaner: improve readability

* Add google::EnableLogCleaner() to windows logging.h

* logging: log_cleaner: Remove perror message

* logging: IsGlogLog: match filename keyword by keyword

Splitting a filename into tokens by '.' causes problems
if the executable's filename contains a dot.

Filename should be matched keyword by keyword in the following
order:
1. program name
2. hostname
3. username
4. "log"

Extend the LogSink interface to be able to pass microseconds

Added fixed log name support

Allow getpwuid_r to return missing entry.

Respect configured docdir

Use thread local for libunwind GetStackTrace() reentrancy protection

Fix build for Android API < 21

Fix symbolize_unittest for musl builds

Fix warnings

logging: Fix compilation with uClibc++

googletest: Switch to nanosleep

uClibc++ has compiler support for C++11, but not the functions.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

usleep is deprecated and optionally not available with uClibc-ng.

src/symbolize.cc: fix build without dlfcn.h

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

I supported clang-cl with BUILD_SHARED_LIBS

Ubuntu 14.04 is about to be end-of-life and Bazel CI will stop supporting it shortly afterwards.

Context: https://groups.google.com/d/msg/bazel-dev/_D6XzfNkQQE/8TNKiNmsCAAJ