I build for 2 platforms serially on 2 different build VMs and have the output go to the same common log file.

I use MSBuild to parse that log file for the Win MSBuild related warnings and gcc-4 for the MacOS gcc warnings.

Currently, the MSBuild warning filter is picking up this output from the MacOS build (note the forward slashes among other evidence that show this is not on Windows):

ld: warning: object file compiled with -mlong-branch which is no longer needed. To remove this warning, recompile without -mlong-branch: /usr/lib/gcc/powerpc-apple-darwin10/4.0.1/crt2.o creating bin/paqa_devs
ld: warning: object file compiled with -mlong-branch which is no longer needed. To remove this warning, recompile without -mlong-branch: /usr/lib/gcc/powerpc-apple-darwin10/4.0.1/crt2.o creating bin/patest1

I think the regex needs to be improved for MSBuild to ignore non-Windows output or perhaps the format of the error code (in this case "ld:") should be more strict so as not to allow invalid MSBuild codes (I can't imagine that ld: is a valid MSBuild code).

What this ends up doing is greatly tilting our MSBuild warnings count and including unusable information in the MSBuild warnings result page.