Gcc-arm cross-compiler version

Hi all,
I tried to follow the steps on the following link, to compile firmware for px4-v3 board in an ubuntu 16 machine.
https://ardupilot.org/dev/docs/building-setup-linux.html
I noticed that if i build using the 2017 version of gcc-arm, then i get the following error:
strtof is not part of std
at the end of compilation process. If i use the 2015 version instead, which i took from the archived folder, then it works fine. What can cause this problem? will it work with the latest version of gcc-arm?
Thanks,
Lev