diff --git a/haskell/haskell-lcs/haskell-lcs.SlackBuild b/haskell/haskell-lcs/haskell-lcs.SlackBuild
index 050f7836e5..4b0d4132db 100644
--- a/haskell/haskell-lcs/haskell-lcs.SlackBuild
+++ b/haskell/haskell-lcs/haskell-lcs.SlackBuild
@@ -68,10 +68,13 @@ tar xvf $CWD/$SRCNAM-$VERSION.tar.gz
 cd $SRCNAM-$VERSION
 chown -R root:root .
 find -L . \
- \( -perm 777 -o -perm 775 -o -perm 750 -o -perm 711 -o -perm 555 -o -perm 511 \) \
- -exec chmod 755 {} \; -o \
- \( -perm 666 -o -perm 664 -o -perm 600 -o -perm 444 -o -perm 440 -o -perm 400 \) \
- -exec chmod 644 {} \;
+ \( -perm 777 -o -perm 775 -o -perm 750 -o -perm 711 -o -perm 555 \
+  -o -perm 511 \) -exec chmod 755 {} \; -o \
+ \( -perm 666 -o -perm 664 -o -perm 640 -o -perm 600 -o -perm 444 \
+  -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \;
+
+sed -i -e '1i{-# LANGUAGE FlexibleContexts #-}' \
+  Data/List/LCS/HuntSzymanski.hs
 
 CFLAGS="$SLKCFLAGS" \
 CXXFLAGS="$SLKCFLAGS" \