Fix issues around cc_wrapper with Cabal builds #1350
                
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MAX_PATHon Windows. Since we don't use dynamic Haskell libraries on Windows, we can stick to a shorter build directory path on Windows.cc_wrapper's logic to fix RUNPATHs in temporary outputs of GHC didn't work in a working directory outside of the Bazel execroot as is the case in Cabal builds. This triggered build failures with intermediate outputs exceeding the MACH-O header size limit on MacOS, see Setup ghcide for rules_haskell repository #1262 (comment). This PR extends the corresponding logic in the cc_wrapper to look for the solib directory under the execroot which can be specified by Cabal wrapper via an environment variable.