Log message:
lang/ghc90: import ghc-9.0.1

GHC: The Glasgow Haskell Compiler.

The Glasgow Haskell Compiler is a robust, fully-featured, optimising
compiler for the functional programming language Haskell 98
(http://www.haskell.org). GHC compiles Haskell to either native code
or C. It implements numerous experimental language extensions to
Haskell, including concurrency, a foreign language interface, several
type-system extensions, exceptions, and so on. GHC comes with a
generational garbage collector, a space and time profiler, and a
comprehensive set of libraries.

This package provides the 9.0.x release series.