I have a package that depends on tcl, which is made with threads.
Consequently, the tcl library refers to lots of pthreads symbols.

I have included the tcl buildlink3.mk file in my package Makefile.
However, when configure tries to determine where the tcl library is,
the test program fails because of undefined pthread symbols.  Clearly,
this is because -lpthreads is not included during the test
compilation.

What is the best way to get configure to become aware that it should
include -lpthreads on the command line when compiling the test
program?

Surely, this must be happening in other cases as well and have been
solved already.  Any help is welcome.  Thanks.

Cheers,
Brook