2.5.23: lexer-gcc-3.1.sh doesn't work

[Werner Scheinast]

The script lexer-gcc-3.1.sh (adjustment for flex 2.5.4a) doesn't work in
lilypond 2.5.23. The 'make' command in this script fails. If you remove
the '>/dev/null 2>&1' redirection from the make command, you see the
following messages:

Generating and fixing lily/out-gcc-3.1/lexer.cc... 
../make/stepmake.make:78: ../config-gcc-3.1.make: No such file or 
directory
../make/stepmake.make:103: /stepmake/no-builtin-rules.make: No such file 
or directory
../make/stepmake.make:114: /stepmake/generic-vars.make: No such file or 
directory
../make/stepmake.make:114: /stepmake/c++-vars.make: No such file or 
directory
../make/stepmake.make:114: /stepmake/executable-vars.make: No such file or 
directory
../make/stepmake.make:114: /stepmake/po-vars.make: No such file or 
directory
../make/stepmake.make:114: /stepmake/help2man-vars.make: No such file or 
directory
../make/substitute.make:4: /stepmake/substitute-vars.make: No such file or 
directory
../make/substitute.make:5: /stepmake/substitute-rules.make: No such file 
or directory
../make/stepmake.make:121: /stepmake/generic-rules.make: No such file or 
directory
../make/stepmake.make:121: /stepmake/c++-rules.make: No such file or 
directory
../make/stepmake.make:121: /stepmake/executable-rules.make: No such file 
or directory
../make/stepmake.make:121: /stepmake/po-rules.make: No such file or 
directory
../make/stepmake.make:121: /stepmake/help2man-rules.make: No such file or 
directory
../make/stepmake.make:123: /stepmake/generic-targets.make: No such file or 
directory
../make/stepmake.make:123: /stepmake/c++-targets.make: No such file or 
directory
../make/stepmake.make:123: /stepmake/executable-targets.make: No such file 
or directory
../make/stepmake.make:123: /stepmake/po-targets.make: No such file or 
directory
../make/stepmake.make:123: /stepmake/help2man-targets.make: No such file 
or directory
make: *** No rule to make target `/stepmake/help2man-targets.make'.  Stop.
mv: cannot stat `lily/out-gcc-3.1/lexer.cc': No such file or directory

Of course, these files do exist. Some path(s) might be set wrong.
Because I'm going to update my flex, I'm not concerned much about this. 
However, it should be clarified, either by correcting it or by declaring
flex 2.5.4a as unsupported.

regards,
W. Scheinast