Previously, ast transformations were performed informally as ad-hoc
modifications to the generated C source code. In this commit, the
same transformations are performed by rewriting the ast prior to code
generation time.
The most significant new transformer is transform_assignment_list.
This transforms assignments such as:
a, b, c = f(b, c, d)
To:
a = f(&b, &c, d)
The former syntax is used frequently in the manual's description of
FPU-related instructions.