Error when trying to compile Flipper contract

[stiiifff]

I followed the instructions of the Ask! quickstart over here to create a simple contract, and when I want to compile it, I get the following error:

❯ npx pl-ask-cli compile contracts/index.ts
Build Starting ······
Build progressing. Generating target files ······
ERROR TS2304: Cannot find name 'ASC_RUNTIME'.

     if (ASC_RUNTIME != Runtime.Incremental) {
         ~~~~~~~~~~~
 in ~lib/array.ts(74,9)

ERROR TS2304: Cannot find name 'ASC_RUNTIME'.

     if (ASC_RUNTIME != Runtime.Incremental) {
         ~~~~~~~~~~~
 in ~lib/array.ts(28,9)

ERROR TS2304: Cannot find name 'ASC_RUNTIME'.

     if (ASC_RUNTIME != Runtime.Incremental) {
         ~~~~~~~~~~~
 in ~lib/arraybuffer.ts(21,9)

FAILURE 3 compile error(s)
Build Done. Targets generated. Target directory: /home/steve/Dev/walchain/flipper-ask/build.