Fix oppulance: Explicitly depend on modern flex version

EBRAINS currently has flex@2.6.3, but that version is buggy w.r.t. to "user-defined yy macros" (cf. https://github.com/westes/flex/releases/tag/v2.6.4), which seem to be used by the (particular?) version of binutils used by oppulance.

mentioned in merge request !94 (merged)

mentioned in commit 3a66a577

merged

(Maybe?) Timeout … seems like the change in the version of flex triggers quite some rebuilds.

No worries! The runner was killed but the spawned OKD build job is still running.
When it completes i will update you here!

Hi @emuller ,

It failed.
Logs attached.spack-build-out.txt

Nice, so at least the new flex version does not break anything else .

And regarding the problem here:

../../binutils-gdb/gdb/c-exp.y:3425:1: error: 'void c_print_token(FILE*, int, YYSTYPE)' defined but not used [-Werror=unused-function]
 3425 | c_print_token (FILE *file, int type, YYSTYPE value)
      | ^~~~~~~~~~~~~

Our older gdb version looks like:

#ifdef YYBISON
static void c_print_token (FILE *file, int type, YYSTYPE value);
#define YYPRINT(FILE, TYPE, VALUE) c_print_token (FILE, TYPE, VALUE)
#endif

whereas the current HEAD looks like:

#if defined(YYBISON) && YYBISON < 30800
/* stuff */

which was introduced by "Make c-exp.y work with Bison 3.8+" → we'll fix our version of gdb (i.e. backport this upstream patch to our version, in the long-run we should just move our gdb forward…).