Win fix simple

[jbmohler]

here are two simple fixes culled from #3409 in the efforts to focus the review. I probably shouldn't have batched those items together (not sure of protocol now that I did).

[tacaswell]

I could have sworn that link got fixed already...

[jbmohler]

I can only sigh about that fat-fingered link :)

[tacaswell]

I will merge these as soon as travis passes.

For the other PR just re-base it on top of new v1.4.x head and force-push back to your gh branch.

[tacaswell]

Actually, this made me go back and look at #3477 (which I just cherry-picked back to 1.4.x).

Does that extra searching work on windows to find png.h?

[jbmohler]

No, the extra searching doesn't work on windows. It actually seems that somebody was trying to do something nice (maybe?) with a win32_static pseudo basedir. That may be worth my while for making the windows build slicker overall, but I think it is outside the scope of this PR.

The getstatusoutput code added in 04f13a4 fails on windows for multiple reasons and this PR restores the effective non-check as it happened on windows before that commit.

[tacaswell]

ah, fair enough.