Details:
- Commented out redundant setting of LIBBLIS_LINK within all driver-
level Makefiles. This variable is already set within common.mk, and
so the only time it should be overridden is if the user wants to link
to a different copy of libblis.
- Very minor changes to build/gen-make-frags/gen-make-frag.sh.
- Whitespace and inconsequential quoting change to configure.
- Moved top-level 'windows' directory into a new 'attic' directory.
