i had read about an incident where someone had used portsclean(1) and
lost the base systems gcc-libs, so i used "portsclean -Li" to clean out
old libs after an upgrade.  the output was:

  # portsclean -Li
  ** /usr/local/lib/gcc-4.2.2/libgcc_s.so.1 is shadowed by /lib/libgcc_s.so.1
          /lib/libgcc_s.so.1      <- ?
          /usr/local/lib/gcc-4.2.2/libgcc_s.so.1  <- gcc-4.2.2_20070927
   --> This may be an undesirable situation
  Delete /lib/libgcc_s.so.1
  OK? [no]

  ** /usr/local/lib/gcc-4.2.2/libstdc++.so.6 is shadowed by /usr/lib/libstdc++.so.6
          /usr/lib/libstdc++.so.6 <- ?
          /usr/local/lib/gcc-4.2.2/libstdc++.so.6 <- gcc-4.2.2_20070927
   --> This may be an undesirable situation
  Delete /usr/lib/libstdc++.so.6
  OK? [no]

  ** /usr/local/lib/gcc-4.2.2/libssp.so.0 is shadowed by /lib/libssp.so.0
          /lib/libssp.so.0        <- ?
          /usr/local/lib/gcc-4.2.2/libssp.so.0    <- gcc-4.2.2_20070927
   --> This may be an undesirable situation
  Delete /lib/libssp.so.0
  OK? [no]

  ** /usr/local/lib/gcc-4.2.2/libobjc.so.2 is shadowed by /usr/lib/libobjc.so.2
          /usr/lib/libobjc.so.2   <- ?
          /usr/local/lib/gcc-4.2.2/libobjc.so.2   <- gcc-4.2.2_20070927
   --> This may be an undesirable situation
  Delete /usr/lib/libobjc.so.2
  OK? [no]

  ** /usr/local/lib/gcc-4.2.2/libgomp.so.1 is shadowed by /usr/lib/libgomp.so.1
          /usr/lib/libgomp.so.1   <- ?
          /usr/local/lib/gcc-4.2.2/libgomp.so.1   <- gcc-4.2.2_20070927
   --> This may be an undesirable situation
  Delete /usr/lib/libgomp.so.1
  OK? [no]

using the default left my system intact:

  # ll /lib/libgcc_s.so.1 /usr/lib/libstdc++.so.6 /lib/libssp.so.0 /usr/lib/libobjc.so.2 /usr/lib/libgomp.so.1
       53 -r--r--r--  1 root  wheel  -   56K Sep 24 18:21 /lib/libgcc_s.so.1
       55 -r--r--r--  1 root  wheel  -  9.5K Sep 24 18:21 /lib/libssp.so.0
  1719349 -r--r--r--  1 root  wheel  -   29K Sep 24 18:21 /usr/lib/libgomp.so.1
  1719378 -r--r--r--  1 root  wheel  -  101K Sep 24 18:21 /usr/lib/libobjc.so.2
  1719371 -r--r--r--  1 root  wheel  -  941K Sep 24 18:21 /usr/lib/libstdc++.so.6

i'm not sure what happens when _not_ using the `-i' switch.  the code
seems to indicate that nothing gets deleted by default.  touching
anything in base should be a non-issue IMO, other than adding or
changing symlinks for compatibility like perl-ports do.

i imaging two solutions:  changing portsclean(1) to never touch files in
base or change the various gcc-ports to rename their libs in order to
rule out these name collisions.  the shadowing of vital libs mentioned
in portscleans output is indeed undesirable, unless the port compilers
hard-code library paths.

so my request is to implement either solution, taking care of the
shadowing issue as well.

Fix: 

i'd advise to always use "portsclean -Li" to let it query interactively
in case libraries with identical names exist in both ports and base.

regards, clemens
How-To-Repeat: 
install ports/lang/gcc42 and watch "portsclean -Li".