Instruction for mxe-octave to generate gcc-5.1 mingw complier

[Tatsuro MATSUOKA]

Hello

We have discussed the gcc-4.9.2 generated by mxe-octave on 64 bit build have 
problem
when multilib build are used (it is necessary to use nsis installer which work 
only on 32 bit).

http://octave.1599824.n4.nabble.com/FYI-gcc-4-9-3-td4671271.html


Version up gcc to 5.1.0 seems to resolve the issue.

I would like to try 64bit build on mxe-octave to generate gcc-5.1.0.

I have quick look at the src directory perhaps two patch files are used for 
gcc-4.9.2.
 Are those required for 5.1.0?
 Are additional patches required?

If you show us the instruction, it will be useful to try to build octave on 64 
bit environments.

Tatsuro