CMAKE_PREFIX_PATH and /usr/local

[Dave Horsfall]

On Fri, 15 Jan 2021, Gleb Popov wrote:

>> +if (CMAKE_SYSTEM_NAME MATCHES "BSD")
>> +    include_directories("/usr/local/include")
>
> This is most certainly a wrong thing to do. Instead of simply adding 
> -I/usr/local/include everywhere, you should fix problems for each 
> dependency that the software requires.

What's the problem, exactly?  Ports have always installed themselves under 
/usr/local, and I refuse to overwrite the base system (as Penguin/OS does; 
well, Debian anyway), and the Mac ports system uses /opt/local.

I generally regard the base system i.e. that as distributed as being 
non-userland, and overwritten only with updates.  Backups are much more 
manageable, as I don't have to worry about /bin, /lib etc.

-- Dave