Why /usr/X11R6 before /usr/local?
I installed a new version of zlib from source without using the prefix option of configure (I hate to have to type that everytime, so I just have everything in /usr/local).
Now when I was compiling something that was using zlib headers, I noticed there also was another version of zlib on my system in the /usr/X11R6 directory. This directory is before /usr/local in the search path for both libraries and include files.
Of course I can fix the library path by changing ld.so.conf, but what do I do about the include files? I can now throw away the old zlib from /usr/X11R6, but the next time I upgrade X11 it will install zlib again which will probably again be an older version than the zlib in /usr/local.
Is there a good reason for the /usr/X11R6 path to be before the /usr/local path?