Do not emit size for non-regular files.  There is nothing that
mtree(1) can do in this situation and would cause confusion.

MFC candidate.

Approved by:	re (hrs)
Fix make bootstrapping with WITH_DEBUG_FILES=

A HEAD buildworld on 9.x first bootstraps bmake, but this failed when
building with standalone debug.  Pass in the PROGNAME override to the
'make all' stage as well as 'make install' so that the .debug file is
created with the correct name.

Reviewed by:	sjg
Sponsored by:	The FreeBSD Foundation
Approved by:	re (rodrigc)