GHC fails to compile if source is in /ghc
I was building GHC in a docker image and was ignorant what the $PWD is (it is / in case you were wondering). So I cloned GHC into /ghc, and attempted to build it from there.
Eventually the build fails because there is a sed expression
's|$(TOP)/|...' which rewrites some include paths to nonesense: /usr/lib/ghc/include/... -> /usr/libinclude/...
Anchoring the expression (
's|^$(TOP)/|...') helped the build process to continue past that point, but I haven't completed it due to other issue, so there may be other places where $(TOP) == /ghc breaks the build.