Problem in enabling uvisor - retarget.cpp doesn't compile

[mrudu172]

Following the link provided on the ARMmbed website, I am trying to enable the uvisor - https://docs.mbed.com/docs/mbed-os-api-reference/en/5.1/APIs/security/uvisor/

The first step woks - the "blinky" app works fine. Second step, when trying to enable the uvisor, it is throwing a compile error for the function "retarget.cpp" stating "uvisor_lib_init() was not declared in this scope". This is being used in the function "void software_init_hook()".

I am new to mbed and any help would be appreciated. Thanks!