Need to clarify which gcc-arm-embedded version for compiling

[luc-github]

Hi when use latest gcc-arm-none-eabi-5_3-2016q1-20160330-win32.exe from https://launchpad.net/gcc-arm-embedded
the compilation failed :

error: conflicting types for 'utoa'   
 extern char* utoa( unsigned long value, char *string, int radix );
...
stdlib.h:201:8: note: previous declaration of 'utoa' was here
 char * _EXFUN(utoa,(unsigned, char *, int));

if I use previous version gcc-arm-none-eabi-4_9-2015q3-20150921-win32.exe
I got different warnings (same as travis-ci output) but compilation is Ok

so need to freeze gcc-arm-embedded version or modify makefile to support latest version of gcc-arm-embedded

[luc-github]

May be an easy solution to ensure right version is used is to add a download script with hard coded versions to download like they do for smoothieware : https://github.com/Smoothieware/Smoothieware/blob/edge/win_install.cmd

but it means to add all necessary tools also (at least for window)

Just my 2 cents

[aethaniel]

indeed, ARM GCC releases from this year bring utoa in newlib. The GCC provided with Arduino IDE should work well, being the current reference.