Elad Lahav wrote:

> 1. The line that adds sheap.o in configure.ac is not needed in the
> latest version of the source, as the file is already added if
> HYBRID_MALLOC is defined in src/Makefile.in.

I installed the attached patch to fix that.

> 2. bootstrap-emacs crashes during build due to a stack overflow when
> compiling elisp-mode.elc. Perhaps the result of infinite recursion. Has
> this been observed elsewhere? It doesn't happen on 25.3.

I don't recall seeing it, no. Although this shouldn't prevent building on QNX, 
it does suggest a problem in the QNX implementation, which you should probably 
look into.