libgcc: vxcrtstuff.c: make ctor/dtor functions static

libgcc: vxcrtstuff.c: make ctor/dtor functions static

When the translation unit itself creates pointers to the ctors/dtors
in a specific section handled by the linker (whether .init_array or
.ctors.*), there's no reason for the functions to have external
linkage. That ends up polluting the symbol table in the running
kernel.

This makes vxcrtstuff.c on par with the generic crtstuff.c which also
defines e.g. frame_dummy and __do_global_dtors_aux static.

libgcc/
	* config/vxcrtstuff.c: Make constructor and destructor
	functions static when possible.