clang can't seem to link (some) binaries

[Magnus Eriksson <magetoo%fastmail.fm@localhost>]

When I try using clang, I often see errors similar to this, always related 
to "__sig(.*)set14" :


clang -Os -DUSG -DEUC -I. -I.. 
-DMACDIR='"/usr/local/heirloom/lib/doctools/tmac"' 
-DFNTDIR='"/usr/local/heirloom/lib/doctools/font"' 
-DTABDIR='"/usr/local/heirloom/lib/doctools/nterm"' 
-DHYPDIR='"/usr/local/heirloom/lib/doctools/hyphen"'  -DSHELL='"/bin/sh"' 
-c ../version.c
clang  t10.o t6.o hytab.o n1.o n2.o n3.o n4.o n5.o  n7.o n8.o n9.o ni.o 
nii.o suftab.o makedev.o afm.o otf.o unimap.o  version.o -L../libhnj -lhnj 
-o troff
n2.o: In function `__sigaddset14':
../n2.c:(.text+0x0): multiple definition of `__sigaddset14'
n1.o:../n1.c:(.text+0x0): first defined here
n2.o: In function `__sigdelset14':
../n2.c:(.text+0x32): multiple definition of `__sigdelset14'
n1.o:../n1.c:(.text+0x32): first defined here
n2.o: In function `__sigemptyset14':
../n2.c:(.text+0x99): multiple definition of `__sigemptyset14'
n1.o:../n1.c:(.text+0x99): first defined here
n2.o: In function `__sigfillset14':
../n2.c:(.text+0xbe): multiple definition of `__sigfillset14'
n1.o:../n1.c:(.text+0xbe): first defined here
n2.o: In function `__sigismember14':
../n2.c:(.text+0x66): multiple definition of `__sigismember14'
n1.o:../n1.c:(.text+0x66): first defined here
clang: error: linker command failed with exit code 1 (use -v to see 
invocation)
*** Error code 1

Stop.


Any idea what's going on or how to find out?  I paged through various 
header files to see if there could be anything relevant there, but didn't 
see anything obvious.

I'm on 5.0, clang version is 3.4(nb2), the latest in pkgsrc at the moment. 
(Same thing happened with 3.3.)

The version of gcc that's in 5.0 does not seem to have the same problem.


Magnus