Given the angst that seems to be going on in the time dependency discussion, I thought I would take a look in the other packages in the Haskell Platform and see what extensions are present in the current platform. I figured other people might find this list useful for the sake of this discussion. I found the following dependencies:
CPP:
GLUT, haskell-src, HUnit, network, OpenGL, parallel, QuickCheck, time, regex-posix, stm, zlib, array#, bytestring#, Cabal#, containers#, directory#, filepath#, hpc#, old-time#, packedstring#, process#, random#, syb#, unix#
ForeignFunctionInterface:
editline, GLUT, OpenGL, regex-posix*, time, zlib, array#***, bytestring#, directory#, old-time#, unix#, Win32#
MultiParamTypeClasses:
cgi, mtl, fgl, regex-base, regex-compat, regex-posix, array#**
FunctionalDependencies:
mtl, regex-base, regex-compat, regex-posix
FlexibleInstances:
fgl, mtl, regex-base*, regex-posix*, array#**
ScopedTypeVariables:
fgl, bytestring***, syb#
TypeSynonymInstances:
mtl, regex-base*, regex-posix*, array#**, template-haskell#
ExistentialQuantification:
parsec
OverlappingInstances:
fgl
GeneralizedNewtypeDeriving:
regex-posix*
FlexibleContexts:
regex-base*, regex-posix*, array#**
MagicHash:
array***, bytestring***, containers***, template-haskell#
DeriveDataTypeable:
bytestring***, containers***, template-haskell#
Rank2Types:
array***, containers***, syb#
UnboxedTuples:
array***, bytestring***
UnliftedFFITypes:
array***, bytestring***
PatternSignatures:
syb#****
PatternGuards:
template-haskell#
PolymorphicComponents:
template-haskell#
EmptyDataDecls:
unix#
???:
ghc-prim#, integer#
* w/ split base
** except on nhc-98
*** only for ghc
**** only for old versions of ghc < 6.10
# ghc 6.10.3 core library, not included directly, but implied