fatal internal error, bad line in skeleton file

[arekm]

On Linux 5.8 with glibc 2.32

$ flex --version
flex 2.6.4
$ flex -Pzend -Sflex.txt -o x.c -i zls.txt
flex: fatal internal error, bad line in skeleton file

and the weird thing is that it worked before (but many things has changed since then like glibc, gcc etc)

flex.txt zls.txt

[zmajeed]

You may find my comment and script in https://github.com/westes/flex/issues/303 useful. From what you describe it seems the skeleton file format has changed in incompatible ways