Without the change build fails on `master` as
https://hydra.nixos.org/build/250334809:
In file included from /build/source/srsue/hdr/phy/phy_metrics.h:26,
from /build/source/srsue/hdr/phy/phy_common.h:25,
from /build/source/srsue/src/phy/phy_common.cc:26:
In member function 'std::array<_Tp, _Nm>::value_type& std::array<_Tp, _Nm>::operator[](size_type) [with _Tp = float; long unsigned int _Nm = 5]',
inlined from 'void srsue::phy_common::reset_measurements(uint32_t)' at /build/source/srsue/src/phy/phy_common.cc:662:18,
inlined from 'void srsue::phy_common::reset()' at /build/source/srsue/src/phy/phy_common.cc:918:21:
/nix/store/qs1nwzbp2ml3cxzsxihn82hl0w73snr0-gcc-13.2.0/include/c++/13.2.0/array:203:24: error: array subscript 5 is above array bounds of 'std::__array_traits<float, 5>::_Type' {aka 'float [5]'} [-Werror=array-bounds=]
203 | return _M_elems[__n];
| ~~~~~~~~^
Blanket `-Werror` is prone to build failures on newer toolchains.
Disable it via exposed `cmake` configure knob.
