unsetenv not found under Solaris 8 when building ghc-6.10.1

Which library provides unsetenv?

Building ghc-bin-6.10.1...
[1 of 1] Compiling Main             ( Main.hs, dist-stage2/build/ghc/ghc-tmp/Main.o )
Linking dist-stage2/build/ghc/ghc ...
/home/maeder/haskell/solaris/ghc-6.10.1/libraries/unix/dist/build/libHSunix-2.3.1.0.a(HsUnix.o): In function `__hsunix_unsetenv':
HsUnix.c:(.text+0x138): undefined reference to `unsetenv'
collect2: ld returned 1 exit status
gmake[3]: *** [build.stage.2] Error 1
gmake[3]: Leaving directory `/home/maeder/haskell/solaris/ghc-6.10.1/ghc'
gmake[2]: *** [build.stage.2] Error 2
gmake[2]: Leaving directory `/home/maeder/haskell/solaris/ghc-6.10.1/compiler'
gmake[1]: *** [stage2] Error 2
gmake[1]: Leaving directory `/home/maeder/haskell/solaris/ghc-6.10.1'
gmake: *** [bootstrap2] Error 2

SunOS 5.8 Generic_117350-57 sun4u sparc SUNW,Ultra-4

-bash-3.00$ gcc -v
Using built-in specs.
Target: sparc-sun-solaris2.8
Configured with: ../gcc-4.0.3/configure --prefix=/usr/local/lang -program-suffix=_4.0.3 --with-gnu-as --with-as=/usr/local/bin/gnu-as --with-gnu-ld --with-ld=/usr/local/bin/gnu-ld --enable-version-specific-runtime-libs --enable-languages=c,c++
Thread model: posix
gcc version 4.0.3

Trac metadata

Trac field	Value
Version	6.10.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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