bsd.port.mk that will be committed soon, this will disable automatic
package building when PACKAGE_BUILDING is defined (so they can be
built from separate scripts).
These are no-ops for ordinary users (i.e., when PACKAGE_BUILDING is
not defined).
"?=" to "=" for MAKE_FLAGS, bsd.port.mk is read later anyway. Change
"/usr/local" to "${PREFIX}" and "/usr/bin/false" to ${FALSE}. Remove
spurious empty lines.
Many of the above found by: portlint
