BUILD TOOLCHAIN FOR ARM

HI, I wanted to build the tool chain for arm processor and to set up genode by qemu emulator. But when i build the genode tool chain for arm..it is asking for missing tools.

athul@athul-HP-Pavilion-Notebook:~/genode/tool$ ./tool_chain Need to have GNAT installed and the GNAT version must match the GCC version (found GCC 7). tool_chain:155: *** Please install missing tools.. Stop. athul@athul-HP-Pavilion-Notebook:~/genode/tool$

I have installed the same versions for gcc and gnat. Can you help me?