build: Upgrades version of googletest to live at head.

The tagged versions of Googletest are considered obsolete. The
recommended version is the one targeted by the `main` branch.

This patch adds an include to `optional_io.hpp`, because a change
in googletest caused one of our tests to try to output a
`boost::optional`.


Integration breaking change: the GOOGLETEST_VERSION CMake variable is no
longer honored.

Change-Id: Ie816821af53a79842ddad4f2e5c56e26a2e20782
Reviewed-on: http://gerrit2.aldebaran.lan/1761
Reviewed-by: philippe.martin <philippe.martin@softbankrobotics.com>
Reviewed-by: jmonnon <jmonnon@aldebaran.com>
Tested-by: vincent.palancher <vincent.palancher@softbankrobotics.com>

Author: Vincent Palancher

cmake/set_dependencies.cmake

@@ -58,16 +58,13 @@ overridable_variable(PYBIND11_GIT_REPOSITORY https://github.com/pybind/pybind11)
 # `ExternalProject` module documentation of the `GIT_TAG` argument.
 overridable_variable(PYBIND11_GIT_TAG v${PYBIND11_VERSION})
 
-# Version of googletest to use.
-overridable_variable(GOOGLETEST_VERSION 1.10.0)
-
 # URL of the git repository from which to download googletest. For more details, see CMake
 # `ExternalProject` module documentation of the `GIT_REPOSITORY` argument.
 overridable_variable(GOOGLETEST_GIT_REPOSITORY https://github.com/google/googletest.git)
 
 # Git branch name, tag or commit hash to checkout for googletest. For more details, see CMake
 # `ExternalProject` module documentation of the `GIT_TAG` argument.
-overridable_variable(GOOGLETEST_GIT_TAG release-${GOOGLETEST_VERSION})
+overridable_variable(GOOGLETEST_GIT_TAG main)
 
 set(PYTHON_VERSION_STRING "" CACHE STRING "Version of Python to look for. This \
 variable can be specified by tools run directly from Python to enforce the \

tests/test_object.cpp

@@ -14,6 +14,7 @@
 #include <gtest/gtest.h>
 #include <gmock/gmock-matchers.h>
 #include <gmock/gmock.h>
+#include <boost/optional/optional_io.hpp>
 #include "common.hpp"
 
 namespace py = pybind11;