Patch by Davin Potts.

(tclTomMath.h was broken) and non-final Tcl 8.6.

Patch by Van Lindberg.

Patch by Alex Shkop.

Patch by Stéphane Wirtel.

   party sources. Run aclocal to import it to aclocal.m4 and add aclocal.m4
   to the archive.

Using LF can a script to fail if it tries to use a label that is
split across 512 byte blocks.  Who knows why.

It's still not necessary to build, but may be useful to some.

In some Tcl versions -2147483648 is wide integer.

robust at shutdown. If needs to release multiple resources, they are released
even if errors are occured.

This will prevent failures from the version of NASM installed on buildbots,
if the ability to override the version used is desired again later, we can
figure out a way to opt in.

"Pipes and Queues" and "Synchronization between processes" subsections.

Patch by Davin Potts.