Once installed the things in gccbin gccinc and gcclib you should try
the following, to see if anything works.

Create a file test.c containing (the old favorite)

   #include <stdio.h>
   main()
   {
      printf("Hello world\n");
   }


Compile it as follows

   gcc test.c
   gcc2minix < a.out >test
   chmod +x test   # may not be necessary depending on your umask
   ./test

Should print Hello world.