To get an idea of what is in a typical toolchain, I want to examine the crosstool-NG toolchain you have just created. The examples use the ARM Cortex A8 toolchain created for the BeagleBone Black, which has the prefix arm-cortex_a8-linux-gnueabihf-. If you built the ARM926EJ-S toolchain for the QEMU target, then the prefix will be arm-unknown-linux-gnueabi instead.
The ARM Cortex A8 toolchain is in the directory ~/x-tools/arm-cortex_a8-linux-gnueabihf/bin. In there you will find the cross compiler, arm-cortex_a8-linux-gnueabihf-gcc. To make use of it, you need to add the directory to your path using the following command:
$ PATH=~/x-tools/arm-cortex_a8-linux-gnueabihf/bin:$PATH
Now you can take a simple helloworld program, which in the C language looks like this:
#include <stdio.h>
#include <stdlib.h>
int main (int argc, char *argv[])
{
printf...