If you wish to build the object files and executables in a directory other than the one containing the source files, here is what you must do differently:
Make sure you have a version of Make that supports the VPATH feature. (GNU Make supports it, as do Make versions on most BSD systems.)
If you have ever run `configure' in the source directory, you must undo the configuration. Do this by running:
make distclean
Go to the directory in which you want to build the compiler before running `configure':
mkdir gcc-sun3 cd gcc-sun3
On systems that do not support symbolic links, this directory must be on the same file system as the source code directory.
Specify where to find `configure' when you run it:
../gcc/configure ...
This also tells configure where to find the compiler sources; configure takes the directory from the file name that was used to invoke it. But if you want to be sure, you can specify the source directory with the `--srcdir' option, like this:
../gcc/configure --srcdir=../gcc other options
The directory you specify with `--srcdir' need not be the same as the one that configure is found in.
Now, you can run make in that directory. You need not repeat the configuration steps shown above, when ordinary source files change. You must, however, run configure again when the configuration files change, if your system does not support symbolic links.