apcupsd: fix gcc 13 compliation error

apcupsd: fix gcc 13 compliation error

On GCC13 build fails:

toolchain-mipsel_24kc_gcc-13.2.0_musl/lib/libsupc++.a(eh_alloc.o): in function `std::__sv_check(unsigned int, unsigned int, char const*)':
toolchain-mipsel_24kc_gcc-13.2.0_musl/gcc-13.2.0-final/mipsel-openwrt-linux-musl/libstdc++-v3/include/string_view:73:
undefined reference to `std::__throw_out_of_range_fmt(char const*, ...)'
collect2: error: ld returned 1 exit status
make[5]: *** [Makefile:33: apcupsd] Error 1

Workaround found at https://lore.kernel.org/buildroot/87wmsbk386.fsf@48ers.dk/T/

Signed-off-by: Ivan Pavlov <AuthorReflex@gmail.com>