Hello,
Without stream modules, nginx cross compiles well.

With stream modules, I see the below error:
buildmachine:nginx-1.12.0_ppc[sim-qnx-r18.x]$vim src/core/ngx_rwlock.c
buildmachine:nginx-1.12.0_ppc[sim-qnx-r18.x]$make
make -f objs/Makefile
make[1]: Entering directory '/home/dyadavalli/nginx/nginx-1.12.0_ppc'
qcc -c -V 4.4.2,gcc_ntoppcbe -DNGX_SYS_NERR=135 -DNGX_HAVE_MAP_ANON -DNGX_PTR_SIZE=4 -DNGX_SIZE_T_LEN=10 -DNGX_MAX_SIZE_T_VALUE=2147483647 -DNGX_MAX_OFF_T_VALUE=2147483647 -DNGX_MAX_TIME_T_VALUE=2147483647 -DNGX_OFF_T_LEN=10 -DNGX_TIME_T_LEN=10 -DNGX_HAVE_MSGHDR_MSG_CONTROL -I~/myopenssl_ppc/include/ -I src/core -I src/event -I src/event/modules -I src/os/unix -I /home/dyadavalli/nginx-1.12.0_ppc/nginx_conf -I /home/dyadavalli/myopenssl_ppc/include -I objs \
-o objs/src/core/ngx_rwlock.o \
src/core/ngx_rwlock.c
src/core/ngx_rwlock.c:116:2: error: #error ngx_atomic_cmp_set() is not defined!
cc: /opt/QNX651/host/linux/x86/usr/lib/gcc/powerpc-unknown-nto-qnx6.5.0/4.4.2/cc1 error 1
make[1]: *** [objs/Makefile:619: objs/src/core/ngx_rwlock.o] Error 1
make[1]: Leaving directory '/home/dyadavalli/nginx-1.12.0_ppc'
make: *** [Makefile:8: build] Error 2
buildmachine:nginx-1.12.0_ppc[sim-qnx-r18.x]$

I read that nginx has built in libatomic sources. Could you please tell me how to use it via configure script.

Thanks for help.