others are untested and some are likely broken. add this config option
before including config.mak rather than after so that the user can
override it in config.mak if desired.
multilib would not be usable without building multiple versions of
musl anyway, which we don't yet support, so enabling it does not make
sense. due to bugs in gcc's build system, even with multilib disabled,
multilib dir structures get used on 64-bit archs leading to target
libs being installed in /lib64 (or /libx32, etc.) under the sysroot,
rather than /lib. fix this by suppressing the variable that controls
it.
blanking INFO_DEPS suffices to prevent attempts to rebuild the docs,
but does not reliably suppress their installation. blanking infodir
does the latter. there are other methods that work too but this seems
to be the simplest.
nothing in a normal gcc/binutils actually uses flex and bison, but
this useless test for the output filename lex produces breaks the
build unless [f]lex is installed. the result of this check is
specified by posix anyway, so hard-code the specified result.