Replace C files in the runtime with generated code

[emwap]

Background

Some runtime support files in lib/Feldspar/C have caused problems when linking on Ubuntu (see #26).

The intention of the files (feldspar_(c99|tic64x).{hc}) is to enable different implementations of runtime support functions on different platforms.

However, there are a few problems with this solution.

• GHC and GHCi uses different linkers which can have surprising results on different architectures.
• Most of the functions are small and should really be implemented as inline in the corresponding header file to allow optimization by the C compiler.
• We have more information in the language than a C compiler (ranges etc) can gather, so we are missing an optimization opportunity by introducing the code this late in the chain.

Tasks

• Remove most of the functions from the files in the lib/Feldspar/C directory.
• Generate the small functions as part of the target specialization phase of optimization (Add support for rewrites in targetSpecialization feldspar-language#60)