cc/gcc: frontends are responsible for selecting the list of languages

Do for the final step the same as for the core step: compute the list
of selected langauages from the frontend, not in the backend.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

cc/gcc: pass the language list to the core backend

As the core backend can be used to also build the bare-metal compiler,
we have to tel it what languages to build.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

cc/gcc: add language helper function

Add a function that prepares the language configure option.
It is needed in at least two places, some commonalisation is needed. ;-)

Unfortunately, it is no longer possible to print warnings about experimental
languages any more. Anyway, the experimental status is clearly indicated
in the menuconfig. so it should not be a surprise if the build breaks. :-/

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

complibs: fixup the host complibs install dir

It's easier to have as much as possible stuff in the same place to
ease backup/restore, and make things easier to follow.

Move the host companion libraries install dir as a sub-dir of the
build-tools install dir (but not directly in it, it would break
for canadian or cross-native).

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

cc/gcc: cleanup the frontends

A few noop fix-ups:
- fix the comments in core pass-1
- commonalise settings that can be

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

complibs: add frontends for building to run on the build machine

In canadian-cross, we need the companion libraries running on the
build machine, to be able to build the two core gcc.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

binutils: add frontends for building to run on the build machine

In canadian-cross, we need binutils running on the build machine to be
able to build the target C library.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

complibs: split companion libraries to backend/frontend, a-la cc_core

Move the actual complibs codes to backend functions that builds the
required combo of build/host/target as requested by a frontend.

This split is currently a no-op, but is required for the upcoming
canadian-cross rework, where we'll be needing to build the complibs
twice, one for build/build, and one for build/host.

This applies to the six companion libraries:
- GMP
- MPFR
- PPL
- Cloog/PPL
- MPC
- libelf

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

binutils: split binutils to backend/frontend, a-la cc_core

Move the actual binutils code to a backend function that builds the
required combo of build/host/target as requested by a frontend.

This split is currently a no-op, but is required for the upcoming
canadian-cross rework, where we'll be needing to build two binutils,
one for build/build/target, and one for build/host/target.

This applies to the three binutils:
- GNU binutils
- elf2flt
- sstrip

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

cc/gcc: always build core compilers to run on the build machine

The core compilers are used to build the C library, so they
should always run on the build machine, not on the host.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>