I am making for QNX 6.3.2 on a Linux server. I have two copies of OpenSSH (and OpenSSL): one to make for a PPC target and one for an X86 target:

./configure --build=i686-pc-linux-gnu --host=powerpc-unknown-nto-qnx6.3.0 --prefix= CC=ntoppc-gcc CFLAGS='-fPIC -I/home/williams/openss/openssl/ppc/install/include' LDFLAGS='-L/opt/qnx632/target/qnx6/ppcbe/lib -L/opt/qnx632/target/qnx6/ppcbe/usr/lib -L/home/williams/openss/openssl/ppc/install/lib' --sysconfdir=/etc/ssh

./configure --build=i686-pc-linux-gnu –host=i386-pc-nto-qnx6.3.0 --prefix= CC=ntox86-gcc CFLAGS='-fPIC -I/home/williams/openss/openssl/x86/install/include' LDFLAGS='-L/opt/qnx632/target/qnx6/x86/lib -L/opt/qnx632/target/qnx6/x86/usr/lib -L/home/williams/openss/openssl/x86/install/lib' --sysconfdir=/etc/ssh

The file monitor_fdpass.c cannot find the file poll.h since it is in the /usr/include/sys directory.  The HAVE_POLL_H is not defined and HAVE_SYS_POLL_H is defined; both are correctly set. mux.c, scp.c, monitor.c, atomicio.c all say:

#ifdef HAVE_POLL_H
#include <poll.h>
#else
# ifdef HAVE_SYS_POLL_H
#  include <sys/poll.h>
# endif
#endif

The only file that does not say this is monitor_fdpass.c which says:

#ifdef HAVE_POLL_H
#include <poll.h>
#endif

and, of course, it cannot find poll.h for my system for that reason. I modified this .c file to match the others to get the system to compile and I think this should apply to the general distribution as well.