When you build a component using the proprietor method, the main difference is that the build directory merges the source files from different directories in the source tree to a merged build directory. These files are present in the build-component tree via symbolic links. The merged tree is created by the mkmerge tool.
All built files are in the directory in the build-component tree in the same location as the source link. This enables you to mix generic and specific source code, from different source tree directories, in the same component directory.
To recapitulate, the main tasks performed by a mkmk build are the following:
The "all" makefile target in the Makefile.src of the component invokes mkmerge to build the merged tree
The makefiles are built in the merged tree with the mkmk tool
Finally, make is invoked to generate the object files, libraries and binaries