[boost] [optional] Warnings about uninitialized values

Subject: [boost] [optional] Warnings about uninitialized values
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2014-06-21 18:28:24

Hi,

When I use boost::optional I often see gcc warnings about using possibly 
uninitialized values. I've seen such warnings in my projects outside Boost but 
now I encountered them in Boost.Log. Building the current develop with gcc 4.8 
I see this:

./boost/date_time/constrained_value.hpp: In member function 
‘boost::shared_ptr<boost::log::v2_mt_posix::sinks::sink> 
boost::log::v2_mt_posix::
{anonymous}::default_text_file_sink_factory<CharT>::create_sink(const 
settings_section&) [with CharT = wchar_t; boost::log::v2_mt_posix::
{anonymous}::default_text_file_sink_factory<CharT>::settings_section = 
boost::log::v2_mt_posix::basic_settings_section<wchar_t>]’:
./boost/date_time/constrained_value.hpp:76:7: warning: ‘*((void*)& day +2)’ 
may be used uninitialized in this function [-Wmaybe-uninitialized]
       value_ = value;
       ^
libs/log/src/init_from_settings.cpp:172:32: note: ‘*((void*)& day +2)’ was 
declared here
     optional< unsigned short > day;
                                ^
libs/log/src/init_from_settings.cpp:249:87: warning: ‘*((void*)& weekday +4)’ 
may be used uninitialized in this function [-Wmaybe-uninitialized]
         return sinks::file::rotation_at_time_point(weekday.get(), hour, 
minute, second);
                                                                                       ^
libs/log/src/init_from_settings.cpp:171:37: note: ‘*((void*)& weekday +4)’ was 
declared here
     optional< date_time::weekdays > weekday;
                                     ^
I attached the full log for convenience. The code in question is this 
function:

https://github.com/boostorg/log/blob/develop/src/init_from_settings.cpp#L171

Note that at line 248 and below I check that the optional is filled before 
using it, so there is no way I'll be accessing any uninitialized data (that 
is, if boost::optional behaves correctly).

I suspect this may be a compiler bug. I tried to create a minimal example to 
reproduce it but the warning doesn't show in a simple context. However, I'd 
like it to be worked around somehow (unless it's an actual bug in 
boost::optional).

Any suggestions? Am I missing a bug in my code?

Performing configuration checks

    - symlinks supported       : yes (cached)
    - x86                      : yes (cached)
    - compiler-supports-ssse3  : yes (cached)
    - has_icu builds           : yes (cached)
    - lockfree boost::atomic_flag : yes (cached)
    - compiler-supports-avx2   : yes (cached)

Component configuration:

    - atomic                   : not building
    - chrono                   : not building
    - container                : not building
    - context                  : not building
    - coroutine                : not building
    - date_time                : not building
    - exception                : not building
    - filesystem               : not building
    - graph                    : not building
    - graph_parallel           : not building
    - iostreams                : not building
    - locale                   : not building
    - log                      : building
    - math                     : not building
    - mpi                      : not building
    - program_options          : not building
    - python                   : not building
    - random                   : not building
    - regex                    : not building
    - serialization            : not building
    - signals                  : not building
    - sync                     : not building
    - system                   : not building
    - test                     : not building
    - thread                   : not building
    - timer                    : not building
    - wave                     : not building

...patience...
...patience...
...patience...
...patience...
...found 7290 targets...
...updating 149 targets...
common.mkdir stage
common.mkdir bin.v2/libs
common.mkdir bin.v2/libs/filesystem
common.mkdir bin.v2/libs/regex
common.mkdir bin.v2/libs/thread
common.mkdir bin.v2/libs/date_time
common.mkdir bin.v2/libs/system
common.mkdir bin.v2/libs/chrono
common.mkdir bin.v2/libs/log
common.mkdir bin.v2/libs/chrono/build
common.mkdir bin.v2/libs/thread/build
common.mkdir bin.v2/libs/log/build
common.mkdir bin.v2/libs/system/build
common.mkdir bin.v2/libs/regex/build
common.mkdir bin.v2/libs/chrono/build/gcc-4.8
common.mkdir bin.v2/libs/thread/build/gcc-4.8
common.mkdir bin.v2/libs/filesystem/build
common.mkdir bin.v2/libs/date_time/build
common.mkdir stage/lib
common.mkdir bin.v2/libs/regex/build/gcc-4.8
common.mkdir bin.v2/libs/system/build/gcc-4.8
common.mkdir bin.v2/libs/log/build/gcc-4.8
common.mkdir bin.v2/libs/date_time/build/gcc-4.8
common.mkdir bin.v2/libs/filesystem/build/gcc-4.8
common.mkdir bin.v2/libs/thread/build/gcc-4.8/release
common.mkdir bin.v2/libs/log/build/gcc-4.8/release
common.mkdir bin.v2/libs/chrono/build/gcc-4.8/release
common.mkdir bin.v2/libs/regex/build/gcc-4.8/release
common.mkdir bin.v2/libs/thread/build/gcc-4.8/release/debug-symbols-on
common.mkdir bin.v2/libs/chrono/build/gcc-4.8/release/debug-symbols-on
common.mkdir bin.v2/libs/system/build/gcc-4.8/release
common.mkdir bin.v2/libs/date_time/build/gcc-4.8/release
common.mkdir bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on
common.mkdir bin.v2/libs/date_time/build/gcc-4.8/release/debug-symbols-on
common.mkdir bin.v2/libs/filesystem/build/gcc-4.8/release
common.mkdir bin.v2/libs/system/build/gcc-4.8/release/debug-symbols-on
common.mkdir bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on
common.mkdir bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix
common.mkdir bin.v2/libs/thread/build/gcc-4.8/release/debug-symbols-on/threading-multi
common.mkdir bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi
common.mkdir bin.v2/libs/chrono/build/gcc-4.8/release/debug-symbols-on/threading-multi
common.mkdir bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on
common.mkdir bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi
common.mkdir bin.v2/libs/system/build/gcc-4.8/release/debug-symbols-on/threading-multi
common.mkdir bin.v2/libs/date_time/build/gcc-4.8/release/debug-symbols-on/threading-multi
common.mkdir bin.v2/libs/thread/build/gcc-4.8/release/debug-symbols-on/threading-multi/pthread
common.mkdir bin.v2/libs/date_time/build/gcc-4.8/release/debug-symbols-on/threading-multi/gregorian
common.mkdir bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on/threading-multi
gcc.compile.c++ bin.v2/libs/thread/build/gcc-4.8/release/debug-symbols-on/threading-multi/future.o
gcc.compile.c++ bin.v2/libs/system/build/gcc-4.8/release/debug-symbols-on/threading-multi/error_code.o
gcc.compile.c++ bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on/threading-multi/codecvt_error_category.o
gcc.link.dll bin.v2/libs/system/build/gcc-4.8/release/debug-symbols-on/threading-multi/libboost_system.so.1.56.0
common.copy stage/lib/libboost_system.so.1.56.0
ln-UNIX stage/lib/libboost_system.so
gcc.compile.c++ bin.v2/libs/chrono/build/gcc-4.8/release/debug-symbols-on/threading-multi/thread_clock.o
gcc.compile.c++ bin.v2/libs/chrono/build/gcc-4.8/release/debug-symbols-on/threading-multi/chrono.o
gcc.compile.c++ bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on/threading-multi/path_traits.o
gcc.compile.c++ bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on/threading-multi/utf8_codecvt_facet.o
gcc.compile.c++ bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on/threading-multi/portability.o
gcc.compile.c++ bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on/threading-multi/windows_file_codecvt.o
gcc.compile.c++ bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on/threading-multi/unique_path.o
gcc.compile.c++ bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on/threading-multi/path.o
gcc.compile.c++ bin.v2/libs/thread/build/gcc-4.8/release/debug-symbols-on/threading-multi/pthread/once.o
gcc.compile.c++ bin.v2/libs/date_time/build/gcc-4.8/release/debug-symbols-on/threading-multi/gregorian/date_generators.o
gcc.compile.c++ bin.v2/libs/date_time/build/gcc-4.8/release/debug-symbols-on/threading-multi/gregorian/greg_weekday.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/attribute_name.o
gcc.compile.c++ bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on/threading-multi/operations.o
gcc.link.dll bin.v2/libs/filesystem/build/gcc-4.8/release/debug-symbols-on/threading-multi/libboost_filesystem.so.1.56.0
common.copy stage/lib/libboost_filesystem.so.1.56.0
ln-UNIX stage/lib/libboost_filesystem.so
gcc.compile.c++ bin.v2/libs/date_time/build/gcc-4.8/release/debug-symbols-on/threading-multi/gregorian/greg_month.o
gcc.link.dll bin.v2/libs/date_time/build/gcc-4.8/release/debug-symbols-on/threading-multi/libboost_date_time.so.1.56.0
common.copy stage/lib/libboost_date_time.so.1.56.0
ln-UNIX stage/lib/libboost_date_time.so
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/code_conversion.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/attribute_set.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/attribute_value_set.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/severity_level.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/named_scope.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/process_id.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/global_logger_storage.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/thread_id.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/default_attribute_names.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/record_ostream.o
gcc.compile.c++ bin.v2/libs/thread/build/gcc-4.8/release/debug-symbols-on/threading-multi/pthread/thread.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/process_name.o
gcc.link.dll bin.v2/libs/thread/build/gcc-4.8/release/debug-symbols-on/threading-multi/libboost_thread.so.1.56.0
common.copy stage/lib/libboost_thread.so.1.56.0
ln-UNIX stage/lib/libboost_thread.so
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/timer.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/once_block.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/thread_specific.o
...on 100th target...
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/timestamp.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/core.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/text_ostream_backend.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/event.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/threadsafe_queue.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/exceptions.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/trivial.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/unhandled_exception_count.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/dump.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/default_sink.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/dump_ssse3.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/syslog_backend.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/dump_avx2.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/parser_utils.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/spirit_encoding.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/init_from_stream.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/format_parser.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/date_time_format_parser.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/named_scope_format_parser.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/text_file_backend.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/filter_parser.o
gcc.compile.c++ bin.v2/libs/chrono/build/gcc-4.8/release/debug-symbols-on/threading-multi/process_cpu_clocks.o
gcc.link.dll bin.v2/libs/chrono/build/gcc-4.8/release/debug-symbols-on/threading-multi/libboost_chrono.so.1.56.0
common.copy stage/lib/libboost_chrono.so.1.56.0
ln-UNIX stage/lib/libboost_chrono.so
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/settings_parser.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/c_regex_traits.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/formatter_parser.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/cpp_regex_traits.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/fileiter.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/matches_relation_factory.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/regex.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/regex_debug.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/regex_raw_buffer.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/regex_traits_defaults.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/static_mutex.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/w32_regex_traits.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/init_from_settings.o
In file included from ./boost/date_time/gregorian/greg_weekday.hpp:12:0,
                 from ./boost/date_time/gregorian/greg_calendar.hpp:13,
                 from ./boost/date_time/gregorian/gregorian_types.hpp:19,
                 from ./boost/date_time/posix_time/posix_time_config.hpp:18,
                 from ./boost/date_time/posix_time/posix_time_system.hpp:13,
                 from ./boost/date_time/posix_time/ptime.hpp:12,
                 from ./boost/date_time/posix_time/posix_time_types.hpp:12,
                 from ./boost/thread/thread_time.hpp:11,
                 from ./boost/thread/lock_types.hpp:18,
                 from ./boost/thread/lock_algorithms.hpp:11,
                 from ./boost/thread/locks.hpp:10,
                 from ./boost/log/sinks/basic_sink_frontend.hpp:32,
                 from ./boost/log/sinks/unlocked_frontend.hpp:24,
                 from ./boost/log/sinks.hpp:22,
                 from libs/log/src/init_from_settings.cpp:45:
./boost/date_time/constrained_value.hpp: In member function ‘boost::shared_ptr<boost::log::v2_mt_posix::sinks::sink> boost::log::v2_mt_posix::{anonymous}::default_text_file_sink_factory<CharT>::create_sink(const settings_section&) [with CharT = wchar_t; boost::log::v2_mt_posix::{anonymous}::default_text_file_sink_factory<CharT>::settings_section = boost::log::v2_mt_posix::basic_settings_section<wchar_t>]’:
./boost/date_time/constrained_value.hpp:76:7: warning: ‘*((void*)& day +2)’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       value_ = value;
       ^
libs/log/src/init_from_settings.cpp:172:32: note: ‘*((void*)& day +2)’ was declared here
     optional< unsigned short > day;
                                ^
libs/log/src/init_from_settings.cpp:249:87: warning: ‘*((void*)& weekday +4)’ may be used uninitialized in this function [-Wmaybe-uninitialized]
         return sinks::file::rotation_at_time_point(weekday.get(), hour, minute, second);
                                                                                       ^
libs/log/src/init_from_settings.cpp:171:37: note: ‘*((void*)& weekday +4)’ was declared here
     optional< date_time::weekdays > weekday;
                                     ^
In file included from ./boost/date_time/gregorian/greg_weekday.hpp:12:0,
                 from ./boost/date_time/gregorian/greg_calendar.hpp:13,
                 from ./boost/date_time/gregorian/gregorian_types.hpp:19,
                 from ./boost/date_time/posix_time/posix_time_config.hpp:18,
                 from ./boost/date_time/posix_time/posix_time_system.hpp:13,
                 from ./boost/date_time/posix_time/ptime.hpp:12,
                 from ./boost/date_time/posix_time/posix_time_types.hpp:12,
                 from ./boost/thread/thread_time.hpp:11,
                 from ./boost/thread/lock_types.hpp:18,
                 from ./boost/thread/lock_algorithms.hpp:11,
                 from ./boost/thread/locks.hpp:10,
                 from ./boost/log/sinks/basic_sink_frontend.hpp:32,
                 from ./boost/log/sinks/unlocked_frontend.hpp:24,
                 from ./boost/log/sinks.hpp:22,
                 from libs/log/src/init_from_settings.cpp:45:
./boost/date_time/constrained_value.hpp: In member function ‘boost::shared_ptr<boost::log::v2_mt_posix::sinks::sink> boost::log::v2_mt_posix::{anonymous}::default_text_file_sink_factory<CharT>::create_sink(const settings_section&) [with CharT = char; boost::log::v2_mt_posix::{anonymous}::default_text_file_sink_factory<CharT>::settings_section = boost::log::v2_mt_posix::basic_settings_section<char>]’:
./boost/date_time/constrained_value.hpp:76:7: warning: ‘*((void*)& day +2)’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       value_ = value;
       ^
libs/log/src/init_from_settings.cpp:172:32: note: ‘*((void*)& day +2)’ was declared here
     optional< unsigned short > day;
                                ^
libs/log/src/init_from_settings.cpp:249:87: warning: ‘*((void*)& weekday +4)’ may be used uninitialized in this function [-Wmaybe-uninitialized]
         return sinks::file::rotation_at_time_point(weekday.get(), hour, minute, second);
                                                                                       ^
libs/log/src/init_from_settings.cpp:171:37: note: ‘*((void*)& weekday +4)’ was declared here
     optional< date_time::weekdays > weekday;
                                     ^
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/wc_regex_traits.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/default_filter_factory.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/usinstances.o
gcc.compile.c++ bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/default_formatter_factory.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/posix_api.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/icu.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/cregex.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/instances.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/wide_posix_api.o
gcc.compile.c++ bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/winstances.o
gcc.link.dll bin.v2/libs/regex/build/gcc-4.8/release/debug-symbols-on/threading-multi/libboost_regex.so.1.56.0
common.copy stage/lib/libboost_regex.so.1.56.0
ln-UNIX stage/lib/libboost_regex.so
gcc.link.dll bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/libboost_log.so.1.56.0
common.copy stage/lib/libboost_log.so.1.56.0
ln-UNIX stage/lib/libboost_log.so
gcc.link.dll bin.v2/libs/log/build/gcc-4.8/release/debug-symbols-on/log-api-unix/threading-multi/libboost_log_setup.so.1.56.0
common.copy stage/lib/libboost_log_setup.so.1.56.0
ln-UNIX stage/lib/libboost_log_setup.so
...updated 149 targets...