This is a new feature where the linker will automatically divide the code into load segments, creating as many segments as necessary to fit it. This relieves the programmer from the need to manually figure out how a large program can be divided into segments.
Auto-segmentation is triggered by the use of the special load segment name AUTOSEG~~~. Using this approach (rather than a flag in the OMF header) allows auto-segmentation to be used with all existing languages that provide a mechanism for specifying load segment names.