cross-compiling issue with process library

Not sure what is the sequence of reporting library issues here, but an attempt to cross-compile x64-linux -> arm-linux fails with error in running configure script in process library. The error is already fixed here: https://github.com/haskell/process/pull/244

Of course to get to this point you need to fix/workaround #21601 (closed). The fix offered there works fine.