When adding files to the annex, the symlinks pointing at the annexed
content are made to have the same mtime as the original file. While git
does not preserve that information, this allows a tool like metastore to be
used with annexed files.
The option cause it to always build to build/Main.o, no matter what
binary it was building. This caused extra work, and in some cases,
could cause the wrong code to be put into the final binary.
