Ada library for interfcaing Ada with C

Hello everybody !!!

I have to interface ADA with C and I would like to create an ADA
library.
I read the gnat manual and it is said that i can use gnatmake and a
project library.
So I use gnatmake:
$  gnatmake -Pmy_lib.gpr

I get the following message:

powerpc-eabispe-gnatbind -n -o b~lib.adb -Llib prog1.ali prog2.ali
powerpc-eabispe-gcc -c b~lib.adb

building static library for project my_lib
powerpc-eabispegnatmake:  powerpc-elf-ar not found in path.


In fact I haven't powerpc-elf-ar on my computer, so i created a link
to it with :
ln -s powerpc-eabispe-ar powerpc-elf-ar
But the problem is the same and all my PATH are good.

My project library my_lib.gpr

/******** Library project*****/
project My_Lib is
  for Source_Dirs use ("SRC");
  for Object_Dir use "CGN";
  for Library_Name use "lib";
  for Library_Dir use "LIB";
  for Library_Kind use "static";
end My_lib;



Because it didn't work, i tried to create a library with the following
command:
powerpc-eabispe-ar rc libmy_lib.a prog1.o prog2.o

but there is an other problem because gnatlink ask me to supply an ALI
file which has a corresponding bind file so I can't create an
executable.
Could you say me how must I use a library file with gnatlink (which
command use) ?

I forgot to say you I use Cygwin a Unix emulator.