Index: ghc6-6.12.1/libraries/unix/configure
===================================================================
--- ghc6-6.12.1.orig/libraries/unix/configure	2010-12-05 12:25:53.134961843 +0000
+++ ghc6-6.12.1/libraries/unix/configure	2010-12-05 12:26:20.744989463 +0000
@@ -6642,6 +6642,9 @@
 	PTHREAD_CFLAGS=-pthread
 	PTHREAD_LDFLAGS=-pthread
 	;;
+linux*)
+	PTHREAD_LIBS=pthread
+	;;
 esac
 
 
Index: ghc6-6.12.1/libraries/unix/configure.ac
===================================================================
--- ghc6-6.12.1.orig/libraries/unix/configure.ac	2010-12-05 12:24:58.524964219 +0000
+++ ghc6-6.12.1/libraries/unix/configure.ac	2010-12-05 12:25:39.134972963 +0000
@@ -211,6 +211,9 @@
 	PTHREAD_CFLAGS=-pthread
 	PTHREAD_LDFLAGS=-pthread
 	;;
+linux*)
+	PTHREAD_LIBS=pthread
+	;;
 esac
 AC_SUBST(PTHREAD_CFLAGS)
 AC_SUBST(PTHREAD_LDFLAGS)
