What would be the best way to compile a project with GDC?

[Gary Willoughby]

I've just finished a project in D and have been using rdmd to 
compile during testing. While this is nice, i now want to try 
other compilers to see if i get any speed gains.

Because i use rdmd it takes care of passing everything to dmd. 
Now i want to try GDC and i need to pass the files in the correct 
order for compilation. I've first tried to write a bash script 
with all the files listed correctly and passed all the necessary 
flags to dmd but i can never get the order of the files correct.

There must be a simpler way to pass these files to dmd in the 
right order? rdmd does it somehow.

Any ideas? How do you handle compiling projects with 50+ source 
files?