How to use glob() to find files recursively?

This is what I have:

glob(os.path.join("src","*.c"))

but I want to search the subfolders of src. Something like this would work:

glob(os.path.join("src","*.c"))
glob(os.path.join("src","*","*.c"))
glob(os.path.join("src","*","*","*.c"))
glob(os.path.join("src","*","*","*","*.c"))

But this is obviously limited and clunky.