treewide: Don't use envHook anymore

This commits needs a MAJOR audit as I oftentimes just guessed which of
`$hostOffset`, `$targetOffset`, or a fixed offset should be used.

pkgs/development/libraries/SDL2/setup-hook.sh

@@ -4,8 +4,4 @@ addSDL2Path () {
   fi
 }
 
-if test -n "$crossConfig"; then
-  crossEnvHooks+=(addSDL2Path)
-else
-  envHooks+=(addSDL2Path)
-fi
+addEnvHooks "$hostOffset" addSDL2Path