Tried to build highlighting-kate-0.2.5 from hackage with ghc-6.12rc1 and could not wait build result. Ghc ate 2.5BG of ram in 6 minutes, then I stopped it as machine swapped horribly.

$ ghc --info
 [("Project name","The Glorious Glasgow Haskell Compilation System")
 ,("Project version","6.12.0.20091010")
 ,("Booter version","6.10.4")
 ,("Stage","2")
 ,("Have interpreter","YES")
 ,("Object splitting","YES")
 ,("Have native code generator","YES")
 ,("Support SMP","YES")
 ,("Unregisterised","NO")
 ,("Tables next to code","YES")
 ,("Win32 DLLs","")
 ,("RTS ways","l debug  thr thr_debug thr_l thr_p  dyn debug_dyn thr_dyn thr_debug_dyn")
 ,("Leading underscore","NO")
 ,("Debug on","False")
 ,("LibDir","/usr/lib64/ghc-6.12.0.20091010")

 * Using cabal-1.8.0.
[1 of 1] Compiling Main             ( /tmp/paludis/dev-haskell-highlighting-kate-0.2.5/work/highlighting-kate-0.2.5/Setup.lhs, /tmp/paludis/dev-haskell-highlighting-kate-0.2.5/work/highlighting-kate-0.2.5/Setup.o )
Linking setup ...
Configuring highlighting-kate-0.2.5...
Flags chosen: executable=True, splitbase=True
Dependency base >=3 && <5: using base-4.2.0.0
Dependency containers -any: using containers-0.3.0.0
Dependency filepath -any: using filepath-1.1.0.3
Dependency parsec <3: using parsec-2.1.0.1
Dependency pcre-light -any: using pcre-light-0.3.1
Dependency xhtml -any: using xhtml-3000.2.0.1
Using Cabal-1.8.0 compiled by ghc-6.12
Using compiler: ghc-6.12.0.20091010

1. ..

/usr/bin/gcc /tmp/paludis/dev-haskell-highlighting-kate-0.2.5/temp/14064.c -o /tmp/paludis/dev-haskell-highlighting-kate-0.2.5/temp/14064 -D__GLASGOW_HASKELL__=612 -I. -O0 -O0 -I/usr/lib64/ghc-6.12.0.20091010/bytestring-0.9.1.5/include -I/usr/lib64/ghc-6.12.0.20091010/base-4.2.0.0/include -I/usr/lib64/ghc-6.12.0.20091010/include -I/usr/lib64/ghc-6.12.0.20091010/include -L/usr/lib64/xhtml-3000.2.0.1/ghc-6.12.0.20091010 -L/usr/lib64/pcre-light-0.3.1/ghc-6.12.0.20091010 -L/usr/lib64/parsec-2.1.0.1/ghc-6.12.0.20091010 -L/usr/lib64/ghc-6.12.0.20091010/filepath-1.1.0.3 -L/usr/lib64/ghc-6.12.0.20091010/containers-0.3.0.0 -L/usr/lib64/ghc-6.12.0.20091010/bytestring-0.9.1.5 -L/usr/lib64/ghc-6.12.0.20091010/array-0.3.0.0 -L/usr/lib64/ghc-6.12.0.20091010/base-4.2.0.0 -L/usr/lib64/ghc-6.12.0.20091010/integer-gmp-0.2.0.0 -L/usr/lib64/ghc-6.12.0.20091010/ghc-prim-0.2.0.0 -L/usr/lib64/ghc-6.12.0.20091010 -L/usr/lib64/ghc-6.12.0.20091010
Preprocessing library highlighting-kate-0.2.5...
Preprocessing executables for highlighting-kate-0.2.5...
Building highlighting-kate-0.2.5...

1. ..

[41 of 61] Compiling Text.Highlighting.Kate.Syntax.Php ( Text/Highlighting/Kate/Syntax/Php.hs, dist/build/Text/Highlighting/Kate/Syntax/Php.p_o )
 
Ctrl+C
VIRT: 2.5G RAM, RSS 1.2G RAM, swap activity is large.