UNIX "ld" command

[sys at Nadc.ARPA]

The manual page for the "ld" command in 4.1 and 4.2 BSD specify
under the "l" option that there are two search paths for libraries,
/lib and /usr/lib. Further down, under FILES, it implies that a
third path exists, /usr/local/lib. The source code reveals that there
is indeed a third path.

We are attempting to maintain upward compatible UNIX software. Can 
anyone (hopefully someone from the labs and from Berkeley) state
whether this third path is specific to BSD and whether it is a feature
which will be supported in future (4.2 and beyond) versions? If
it is intended to be a standard feature, the manual page for the
"l" option should be updated.

Will someone with System V or other UNI*** also tell me whether this
"feature" exists in other UNIX variations?

We intend to use this as a means for average users to have a place
to put default libraries. To do this, /usr/local/lib will need to
be 777 permission. Does anyone see a security or other problem with
this? Finally, if this is not a standard UNIX feature, how would
normal users effectively specifiy a different directory to search
for private libraries? I realize that a library can be specified
in the "ld" command just as a ".o" file can--perhaps this is the
method that  was intended by the designers.

Thanks for any help. I'll post responses if interest warrants.

Jim Reece
SYS at NADC