also, where is the consensus of the class of programs to protect with
USE_FORT taken from? and what's the reason for it?
It takes a considerable amount of time to get large sets of source files
building cleanly with FORTIFY_SOURCE because one finds various failures
to conform to the C standard (non-tolerance of standard functions implemented
as macros in header files) and some genuine and sometimes rather complex
bugs (e.g. the struct ifreq problem). My intent was to get as much value
for the initial investment of time as possible.