Fix curry build

langs/curry.yaml

@@ -5,11 +5,30 @@ aliases:
 name: "Curry"
 
 install:
+  prepare:
     apt:
-    - pakcs
+      - swi-prolog
+  # We are installing from upstream because the Ubuntu 20.10 package
+  # was broken (pakcs wouldn't start up due to swi-prolog being bumped
+  # from 7.x to 8.x, causing a ZIP decoding error).
+  manual: |
+    install -d "${pkg}/opt"
+    install -d "${pkg}/usr/local/bin"
+
+    path="$(curl -fsSL https://www.informatik.uni-kiel.de/~pakcs/download.html | sed '0,/Current release:/d' | grep 'href="download' | grep Linux | grep -Eo 'download/[^"]+' | head -n1)"
+    wget "https://www.informatik.uni-kiel.de/~pakcs/${path}" -O pakcs.tar.gz
+    mkdir pakcs
+    tar -xf pakcs.tar.gz -C pakcs --strip-components=1
+
+    pushd pakcs
+    make PAKCSINSTALLDIR=/opt/pakcs
+    popd
+
+    cp -R pakcs "${pkg}/opt/"
+    ln -s /opt/pakcs/src/pakcs "${pkg}/usr/local/bin/"
 
 repl: |
-  SWIPL=swipl pakcs
+  pakcs
 
 main: "main.curry"
 template: |
@@ -17,7 +36,7 @@ template: |
   main = putStrLn "Hello, world!"
 
 run: |
-  SWIPL=swipl pakcs :load main.curry :eval main
+  pakcs :load main.curry :eval main
 
 scope:
   code: |