Rebaked using post-0.2.7 svn version of bakefile.

Unfortunately 0.2.7 release contained a bug in msvc backend which resulted in
warnings generated for each file compiled. Apply the fix from bakefile svn to
fix this (and test if no other problems are found).

Also update all makefile.unx after changes of r62477.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62488 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775