config: switch cc with libc in the config order

Some of the compiler options depend on the C library choice, (e.g.
whether core passes are needed).

Since the compiler menu comes before the C library menu, those options
may or may not be visible until the C library is chosen, leading to
either options being visible by the user (thus be puzzling as they would
not apply to his case), or invisible to him (yet again puzzling him).

Invert the order of the compiler and the C library in the menuconfig. It
anyway looks more rational, in the end.

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

 # Menu for the native GDB

 config GDB_NATIVE

     bool

     prompt "Native gdb"

     depends on ! BARE_METAL

     depends on ! BACKEND

     help

       Build and install a native gdb for the target, to run on the target.

 if GDB_NATIVE

 config GDB_NATIVE_STATIC

     bool

     prompt "Build a static native gdb"

     help

       In case you have trouble with dynamic loading of shared libraries,

       you will find that a static gdb comes in handy.

 endif # GDB_NATIVE