Bug#1041075: libphonenumber FTBFS with googletest 1.13.0

[Adrian Bunk]

Source: libphonenumber
Version: 8.12.57+ds-3
Severity: serious
Tags: ftbfs trixie sid

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/libphonenumber.html

...
In file included from /usr/include/gtest/gtest-message.h:57,
                 from /usr/include/gtest/gtest-assertion-result.h:46,
                 from /usr/include/gtest/gtest.h:64,
                 from /build/1st/libphonenumber-8.12.57+ds/cpp/test/phonenumbers/asyoutypeformatter_test.cc:23:
/usr/include/gtest/internal/gtest-port.h:270:2: error: #error C++ versions less than C++14 are not supported.
  270 | #error C++ versions less than C++14 are not supported.
      |  ^~~~~
...


This can be fixed by setting CMAKE_CXX_STANDARD to 14
in both cpp/CMakeLists.txt and tools/cpp/CMakeLists.txt