Linux, libtool, and -lpthread

[Russ Allbery]

Hi Scott,

This is just FYI; I'm not sure if you'll run into this anywhere else.

libtool currently has a bug in pthread support with C++: it always links
C++ libraries using -nostdlib, which disables the automatic processing of
-pthread during the link and hence suppresses -lpthread.  The bug
discussion and a bunch of other links is at:

    http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=468555

the most relevant discussion being:

    http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25460

This appears to still be unresolved in Libtool 2.4.2.  This is normally
masked because Xerces-C forces inclusion of -lpthread in its *.la file,
but Debian has dropped the *.la file for Xerces-C (because it adds
spurious dependencies on the ICU libraries), so we now see this problem
for xmltooling (and I'm expecting to see it for others).

I'm working around it for the Debian build by forcing addition of
-lpthread to the linker flags.

-- 
Russ Allbery (rra at debian.org)               <http://www.eyrie.org/~eagle/>