No the original line says
that’s what I changed it from, to nucleo_f429zi, and it still worked.
Even if I rename src\main.c to src\main.cpp (with some (void*) cast fixes) and the appropriate change in zephyr\CMakeLists.txt it still builds.
I then added CONFIG_CPLUSPLUS=y and the build still went through.
Added CONFIG_LIB_CPLUSPLUS=y and CONFIG_STD_CPP11=y and it stell went through.
Added CONFIG_NEWLIB_LIBC=y and it still went through.
Add CONFIG_NEWLIB_LIBC_NANO=n and it broke the build.
c:/users/max/.platformio/packages/toolchain-gccarmnoneeabi@1.80201.190214/bin/../lib/gcc/arm-none-eabi/8.2.1/../../../../arm-none-eabi/bin/ld.exe: C:\Users\Max\.platformio\packages\toolchain-gccarmnoneeabi@1.80201.190214\arm-none-eabi\lib\thumb\v7e-m\nofp\libc.a(lib_a-fini.o): in function `__libc_fini_array':
fini.c:(.text.__libc_fini_array+0x26): undefined reference to `_fini'
collect2.exe: error: ld returned 1 exit status
Changed to CONFIG_NEWLIB_LIBC_NANO=y, cleaned & rebuilt and compilation goes through again.
So for me at least the error is only if CONFIG_NEWLIB_LIBC_NANO=n.