[U-Boot] Writing own Standalone programs

Hi,

I have to write some standalone applications to be run from U-boot. My questions are: 1) Can we include only those header files which are a part of the U-boot code? What needs to be done to use files from the /usr/include/ folder? 2) Does the code for the standalone application be always present in the examples/ folder? 3) Can't we write our own Makefile which will create a .bin and .srec file from a simple C-Program and work from U-boot, instead of compiling entire U-boot?