porting/recompiling GNAT run time library

[fjloma@andaluciajunta.es (Francisco Javier Loma Daza)]

I plan to make a gnat cross compiler to amateur os. I am using
gnat3.14p, and I have tried to use the No_Run_Time pragma,  -nostdinc
and -nostdlib, but my simple program (null body) seems to need some
gnat files, as ada.ads and gnat.ads system.ads, and so on .... one
file that hurts is system.stack_checking because it needs to do a
getenv ....

  Have someone make a minimal custom run time library for use with
gnat No_Run_Time pragma?

Thanks.