Cabal 1.x says:
| Warning: This package indirectly depends on multiple versions of the same
| package. This is highly likely to cause a compile failure.
But in version 2.x, that warning is split into two lines differently:
| Warning:
| This package indirectly depends on multiple versions of the same package. This is very likely to cause a compile failure.
This commit modifies the call to "egrep" to recognize both versions by virtue
of the "-z" flag, which essentially interprets the whole configure-time output
as one long line.
016aa581a7