cc/gcc: build bare-metal gcc statically

- add a new parameter to do_cc_core: build_statically=[yes|no]
- pass build_statically=yes in core_pass_2 when doing bare_metal
- fix handling the static / static libstdc++ / static complibs stuff
- add a commment to keep both blocks (in core and final) in sync

Signed-off-by: "Bryan Hundven" <bryanhundven@gmail.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 # Overall toolchain configuration: paths, jobs, etc...

 # Allow unconditional usage of tristates

 config MODULES

     bool

     default y

 menu "Paths and misc options"

 source "config/global/ct-behave.in"

 source "config/global/paths.in"

 source "config/global/download.in"

 source "config/global/extract.in"

 source "config/global/build-behave.in"

 source "config/global/logging.in"

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