diff -r 160fc94ed49f scripts/build/companion_libs/mpfr.sh
--- a/scripts/build/companion_libs/mpfr.sh	Sun Jan 31 23:04:35 2010 +0100
+++ b/scripts/build/companion_libs/mpfr.sh	Tue Feb 02 23:11:25 2010 +0100
@@ -75,6 +75,7 @@
     case "${CT_HOST}" in
         *cygwin*)   mpfr_opt="--disable-thread-safe";;
         *mingw*)    mpfr_opt="--disable-thread-safe";;
+        *darwin*)   mpfr_opt="--disable-thread-safe";;
         *)          mpfr_opt="--enable-thread-safe";;
     esac