configure --enable-documentation=no doesn't work; fontforge not found

[Peter Ogonek]

Dear members,

I have installed fontforge-20190801, which is not getting detected by lilyponds 
config step.

So I'm trying to compile lilypond master without documentation by

./configure --enable-documentation=no

but this has no effect.

Patching out the search for fontforge by removing
- STEPMAKE_PATH_PROG(FONTFORGE, fontforge, REQUIRED, 20110222)

leads to this error:
Can't exec "@FONTFORGE@": No such file or directory at 
/startdir/src/lilypond/build/scripts/build/out/mf2pt1 line 361.

Cheers,
Peter