Build failure when using gcc-4.9 - signed/unsigned mismatch.

mv -f examples/.deps/persistent_volume_framework-persistent_volume_framework.Tpo examples/.deps/persistent_volume_framework-persistent_volume_framework.Po
g++-4.9 -DPACKAGE_NAME=\"mesos\" -DPACKAGE_TARNAME=\"mesos\" -DPACKAGE_VERSION=\"0.27.0\" -DPACKAGE_STRING=\"mesos\ 0.27.0\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DPACKAGE=\"mesos\" -DVERSION=\"0.27.0\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -DHAVE_DLFCN_H=1 -DLT_OBJDIR=\".libs/\" -DHAVE_PTHREAD_PRIO_INHERIT=1 -DHAVE_PTHREAD=1 -DHAVE_LIBZ=1 -DHAVE_LIBCURL=1 -DHAVE_APR_POOLS_H=1 -DHAVE_LIBAPR_1=1 -DHAVE_SVN_VERSION_H=1 -DHAVE_LIBSVN_SUBR_1=1 -DHAVE_SVN_DELTA_H=1 -DHAVE_LIBSVN_DELTA_1=1 -DHAVE_LIBSASL2=1 -I. -I../../src   -Wall -Werror -DLIBDIR=\"/usr/local/lib\" -DPKGLIBEXECDIR=\"/usr/local/libexec/mesos\" -DPKGDATADIR=\"/usr/local/share/mesos\" -I../../include -I../../3rdparty/libprocess/include -I../../3rdparty/libprocess/3rdparty/stout/include -I../include -I../include/mesos -isystem ../3rdparty/libprocess/3rdparty/boost-1.53.0 -I../3rdparty/libprocess/3rdparty/picojson-1.3.0 -DPICOJSON_USE_INT64 -D__STDC_FORMAT_MACROS -I../3rdparty/libprocess/3rdparty/protobuf-2.5.0/src -I../3rdparty/libprocess/3rdparty/glog-0.3.3/src -I../3rdparty/libprocess/3rdparty/glog-0.3.3/src -I../3rdparty/leveldb/include -I../3rdparty/zookeeper-3.4.5/src/c/include -I../3rdparty/zookeeper-3.4.5/src/c/generated -I../3rdparty/libprocess/3rdparty/protobuf-2.5.0/src -DSOURCE_DIR=\"/Users/till/Development/mesos-private/build/..\" -DBUILD_DIR=\"/Users/till/Development/mesos-private/build\" -I../3rdparty/libprocess/3rdparty/gmock-1.7.0/gtest/include -I../3rdparty/libprocess/3rdparty/gmock-1.7.0/include  -I/usr/local/opt/openssl/include -I/usr/local/opt/libevent/include -I/usr/local/opt/subversion/include/subversion-1 -I/usr/include/apr-1 -I/usr/include/apr-1.0  -D_THREAD_SAFE -pthread -g1 -O0 -Wno-unused-local-typedefs -std=c++11 -DGTEST_USE_OWN_TR1_TUPLE=1 -DGTEST_LANG_CXX11 -MT tests/mesos_tests-container_logger_tests.o -MD -MP -MF tests/.deps/mesos_tests-container_logger_tests.Tpo -c -o tests/mesos_tests-container_logger_tests.o `test -f 'tests/container_logger_tests.cpp' || echo '../../src/'`tests/container_logger_tests.cpp
mv -f slave/qos_controllers/.deps/mesos_tests-load.Tpo slave/qos_controllers/.deps/mesos_tests-load.Po
g++-4.9 -DPACKAGE_NAME=\"mesos\" -DPACKAGE_TARNAME=\"mesos\" -DPACKAGE_VERSION=\"0.27.0\" -DPACKAGE_STRING=\"mesos\ 0.27.0\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DPACKAGE=\"mesos\" -DVERSION=\"0.27.0\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -DHAVE_DLFCN_H=1 -DLT_OBJDIR=\".libs/\" -DHAVE_PTHREAD_PRIO_INHERIT=1 -DHAVE_PTHREAD=1 -DHAVE_LIBZ=1 -DHAVE_LIBCURL=1 -DHAVE_APR_POOLS_H=1 -DHAVE_LIBAPR_1=1 -DHAVE_SVN_VERSION_H=1 -DHAVE_LIBSVN_SUBR_1=1 -DHAVE_SVN_DELTA_H=1 -DHAVE_LIBSVN_DELTA_1=1 -DHAVE_LIBSASL2=1 -I. -I../../src   -Wall -Werror -DLIBDIR=\"/usr/local/lib\" -DPKGLIBEXECDIR=\"/usr/local/libexec/mesos\" -DPKGDATADIR=\"/usr/local/share/mesos\" -I../../include -I../../3rdparty/libprocess/include -I../../3rdparty/libprocess/3rdparty/stout/include -I../include -I../include/mesos -isystem ../3rdparty/libprocess/3rdparty/boost-1.53.0 -I../3rdparty/libprocess/3rdparty/picojson-1.3.0 -DPICOJSON_USE_INT64 -D__STDC_FORMAT_MACROS -I../3rdparty/libprocess/3rdparty/protobuf-2.5.0/src -I../3rdparty/libprocess/3rdparty/glog-0.3.3/src -I../3rdparty/libprocess/3rdparty/glog-0.3.3/src -I../3rdparty/leveldb/include -I../3rdparty/zookeeper-3.4.5/src/c/include -I../3rdparty/zookeeper-3.4.5/src/c/generated -I../3rdparty/libprocess/3rdparty/protobuf-2.5.0/src -DSOURCE_DIR=\"/Users/till/Development/mesos-private/build/..\" -DBUILD_DIR=\"/Users/till/Development/mesos-private/build\" -I../3rdparty/libprocess/3rdparty/gmock-1.7.0/gtest/include -I../3rdparty/libprocess/3rdparty/gmock-1.7.0/include  -I/usr/local/opt/openssl/include -I/usr/local/opt/libevent/include -I/usr/local/opt/subversion/include/subversion-1 -I/usr/include/apr-1 -I/usr/include/apr-1.0  -D_THREAD_SAFE -pthread -g1 -O0 -Wno-unused-local-typedefs -std=c++11 -DGTEST_USE_OWN_TR1_TUPLE=1 -DGTEST_LANG_CXX11 -MT tests/mesos_tests-containerizer.o -MD -MP -MF tests/.deps/mesos_tests-containerizer.Tpo -c -o tests/mesos_tests-containerizer.o `test -f 'tests/containerizer.cpp' || echo '../../src/'`tests/containerizer.cpp
In file included from ../3rdparty/libprocess/3rdparty/gmock-1.7.0/include/gmock/internal/gmock-internal-utils.h:47:0,
                 from ../3rdparty/libprocess/3rdparty/gmock-1.7.0/include/gmock/gmock-actions.h:46,
                 from ../3rdparty/libprocess/3rdparty/gmock-1.7.0/include/gmock/gmock.h:58,
                 from ../../src/tests/container_logger_tests.cpp:21:
../3rdparty/libprocess/3rdparty/gmock-1.7.0/gtest/include/gtest/gtest.h: In instantiation of 'testing::AssertionResult testing::internal::CmpHelperLE(const char*, const char*, const T1&, const T2&) [with T1 = int; T2 = long long unsigned int]':
../../src/tests/container_logger_tests.cpp:467:3:   required from here
../3rdparty/libprocess/3rdparty/gmock-1.7.0/gtest/include/gtest/gtest.h:1579:28: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
 GTEST_IMPL_CMP_HELPER_(LE, <=);
                            ^
../3rdparty/libprocess/3rdparty/gmock-1.7.0/gtest/include/gtest/gtest.h:1562:12: note: in definition of macro 'GTEST_IMPL_CMP_HELPER_'
   if (val1 op val2) {\
            ^
../3rdparty/libprocess/3rdparty/gmock-1.7.0/gtest/include/gtest/gtest.h: In instantiation of 'testing::AssertionResult testing::internal::CmpHelperGE(const char*, const char*, const T1&, const T2&) [with T1 = int; T2 = long long unsigned int]':
../../src/tests/container_logger_tests.cpp:468:3:   required from here
../3rdparty/libprocess/3rdparty/gmock-1.7.0/gtest/include/gtest/gtest.h:1583:28: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
 GTEST_IMPL_CMP_HELPER_(GE, >=);
                            ^
../3rdparty/libprocess/3rdparty/gmock-1.7.0/gtest/include/gtest/gtest.h:1562:12: note: in definition of macro 'GTEST_IMPL_CMP_HELPER_'
   if (val1 op val2) {\
            ^
mv -f tests/.deps/mesos_tests-anonymous_tests.Tpo tests/.deps/mesos_tests-anonymous_tests.Po