haskell/haskell-idna: Fixed SlackBuild.

This won't build without a Unicode locale.
Thanks to samtux.

Signed-off-by: David Spencer <idlemoor@slackbuilds.org>

haskell/haskell-idna/haskell-idna.SlackBuild

@@ -74,6 +74,9 @@ find -L . \
  \( -perm 666 -o -perm 664 -o -perm 640 -o -perm 600 -o -perm 444 \
   -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \;
 
+# Build fails if the locale isn't Unicode, so set this for the build:
+export LANG=en_US.UTF-8
+
 CFLAGS="$SLKCFLAGS" \
 CXXFLAGS="$SLKCFLAGS" \
 runghc Setup configure \