cpphs - 1.20.9.1-4 main

The C pre-processor has been widely used in Haskell source code. It
enables conditional compilation for different compilers, different
versions of the same compiler, and different OS platforms. It is also
occasionally used for its macro language, which can enable certain
forms of platform-specific detail-filling, such as the tedious
boilerplate generation of instance definitions and FFI declarations.
.
However, gcc's cpp has recently been evolving to more strictly adhere
to the C standard. This has had the effect of making it increasingly
incompatible with Haskell's syntax. This is a cpp-a-like designed with
Haskell's syntax in mind.