werror fallout for cross-builds (was: Re: [BUILDROBOT][PATCH] Fix mmix (unused variable))

[Maciej W. Rozycki]

On Tue, 22 Jul 2014, Mike Stump wrote:

> Then IΒ’m shadow boxing.  I assumed that people wanted to turn it on by 
> default.  IΒ’m all for that, I think it is a good idea and a fine 
> direction.  :-)  The only limitation is whitelisting exactly when it 
> pops on and preflighting those at least once to ensure they are clean.

 I think at the very least the thing should be on whenever building with 
itself, that is the build compiler's version is the same as the version of 
the compiler being built.  That can be probably reasonably broadened to 
any compiler bearing the same major.minor version (or just major if we 
switch to the two-part versioning scheme recently proposed).

 The thing is to bring the code base to always compile without warnings 
and then not to let it regress.  Warnings are too easy to miss and 
sometimes are a symptom of actual breakage rather than just harmless 
noise, i.e. code builds and runs, but does something silly.  I have wasted 
hours of debugging time already on chasing such problems.

  Maciej