[Nix-dev] Problem with flex when building from source

[Adam Rosien]

I'm building from source I checked out today and get this error during make:

Making all in libexpr
make[3]: Entering directory `/export/svn/nix/src/libexpr'
/usr/bin/perl ./../aterm-helper.pl nixexpr-ast.hh nixexpr-ast.cc <
./nixexpr-ast.def
/usr/bin/bison -v -o parser-tab.cc ./parser.y -d
./parser.y: conflicts: 1 shift/reduce
/usr/bin/flex --outfile lexer-tab.cc --header-file=lexer-tab.hh ./lexer.l
/usr/bin/flex: unknown flag '-'.  For usage, try
        /usr/bin/flex --help
make[3]: *** [lexer-tab.hh] Error 1
make[3]: Leaving directory `/export/svn/nix/src/libexpr'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/export/svn/nix/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/export/svn/nix'
make: *** [all] Error 2

flex -V reports "flex version 2.5.4".  Is my flex some hideously old
version that it wouldn't accept the gnu-style args?

.. Adam